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<h1>
<small class="visible-xs">Elixir v1.7.2</small>
Keyword
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L1" title="View Source" class="view-source" rel="help">
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<p>A set of functions for working with keywords.</p>
<p>A keyword is a list of two-element tuples where the first
element of the tuple is an atom and the second element
can be any value.</p>
<p>For example, the following is a keyword list:</p>
<pre><code class="nohighlight makeup elixir"><span class="p" data-group-id="5242846366-1">[</span><span class="p" data-group-id="5242846366-2">{</span><span class="ss">:exit_on_close</span><span class="p">,</span><span class="w"> </span><span class="no">true</span><span class="p" data-group-id="5242846366-2">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="5242846366-3">{</span><span class="ss">:active</span><span class="p">,</span><span class="w"> </span><span class="ss">:once</span><span class="p" data-group-id="5242846366-3">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="5242846366-4">{</span><span class="ss">:packet_size</span><span class="p">,</span><span class="w"> </span><span class="mi">1024</span><span class="p" data-group-id="5242846366-4">}</span><span class="p" data-group-id="5242846366-1">]</span></code></pre>
<p>Elixir provides a special and more concise syntax for keyword lists
that looks like this:</p>
<pre><code class="nohighlight makeup elixir"><span class="p" data-group-id="8339581781-1">[</span><span class="ss">exit_on_close</span><span class="p">:</span><span class="w"> </span><span class="no">true</span><span class="p">,</span><span class="w"> </span><span class="ss">active</span><span class="p">:</span><span class="w"> </span><span class="ss">:once</span><span class="p">,</span><span class="w"> </span><span class="ss">packet_size</span><span class="p">:</span><span class="w"> </span><span class="mi">1024</span><span class="p" data-group-id="8339581781-1">]</span></code></pre>
<p>This is also the syntax that Elixir uses to inspect keyword lists:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="p" data-group-id="9810620791-1">[</span><span class="p" data-group-id="9810620791-2">{</span><span class="ss">:active</span><span class="p">,</span><span class="w"> </span><span class="ss">:once</span><span class="p" data-group-id="9810620791-2">}</span><span class="p" data-group-id="9810620791-1">]</span><span class="w">
</span><span class="p" data-group-id="9810620791-3">[</span><span class="ss">active</span><span class="p">:</span><span class="w"> </span><span class="ss">:once</span><span class="p" data-group-id="9810620791-3">]</span></code></pre>
<p>The two syntaxes are completely equivalent. If the keyword has foreign
characters, such as spaces, you can wrap it in quotes:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="p" data-group-id="4431415563-1">[</span><span class="ss">"exit on close"</span><span class="p">:</span><span class="w"> </span><span class="no">true</span><span class="p" data-group-id="4431415563-1">]</span><span class="w">
</span><span class="p" data-group-id="4431415563-2">[</span><span class="ss">"exit on close"</span><span class="p">:</span><span class="w"> </span><span class="no">true</span><span class="p" data-group-id="4431415563-2">]</span></code></pre>
<p>Wrapping a keyword in quotes does not make it a string. Keywords are
always atoms and quotes should only be used to handle foreign characters.
In fact, if you attempt use quotes when not necessary, Elixir will warn.</p>
<p>Note that when keyword lists are passed as the last argument to a function,
if the short-hand syntax is used then the square brackets around the keyword list
can be omitted as well. For example, the following:</p>
<pre><code class="nohighlight makeup elixir"><span class="nc">String</span><span class="o">.</span><span class="n">split</span><span class="p" data-group-id="3236214670-1">(</span><span class="s">"1-0"</span><span class="p">,</span><span class="w"> </span><span class="s">"-"</span><span class="p">,</span><span class="w"> </span><span class="ss">trim</span><span class="p">:</span><span class="w"> </span><span class="no">true</span><span class="p">,</span><span class="w"> </span><span class="ss">parts</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3236214670-1">)</span></code></pre>
<p>is equivalent to:</p>
<pre><code class="nohighlight makeup elixir"><span class="nc">String</span><span class="o">.</span><span class="n">split</span><span class="p" data-group-id="5095993506-1">(</span><span class="s">"1-0"</span><span class="p">,</span><span class="w"> </span><span class="s">"-"</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="5095993506-2">[</span><span class="ss">trim</span><span class="p">:</span><span class="w"> </span><span class="no">true</span><span class="p">,</span><span class="w"> </span><span class="ss">parts</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="5095993506-2">]</span><span class="p" data-group-id="5095993506-1">)</span></code></pre>
<p>A keyword may have duplicated keys so it is not strictly
a key-value store. However most of the functions in this module
behave exactly as a dictionary so they work similarly to
the functions you would find in the <a href="Map.html"><code class="inline">Map</code></a> module.</p>
<p>For example, <a href="Keyword.html#get/3"><code class="inline">Keyword.get/3</code></a> will get the first entry matching
the given key, regardless if duplicated entries exist.
Similarly, <a href="Keyword.html#put/3"><code class="inline">Keyword.put/3</code></a> and <a href="Keyword.html#delete/3"><code class="inline">Keyword.delete/3</code></a> ensure all
duplicated entries for a given key are removed when invoked.
Note that operations that require keys to be found in the keyword
list (like <a href="Keyword.html#get/3"><code class="inline">Keyword.get/3</code></a>) need to traverse the list in order
to find keys, so these operations may be slower than their map
counterparts.</p>
<p>A handful of functions exist to handle duplicated keys, in
particular, <a href="Enum.html#into/2"><code class="inline">Enum.into/2</code></a> allows creating new keywords without
removing duplicated keys, <a href="#get_values/2"><code class="inline">get_values/2</code></a> returns all values for
a given key and <a href="#delete_first/2"><code class="inline">delete_first/2</code></a> deletes just one of the existing
entries.</p>
<p>The functions in <a href="Keyword.html#content"><code class="inline">Keyword</code></a> do not guarantee any property when
it comes to ordering. However, since a keyword list is simply a
list, all the operations defined in <a href="Enum.html"><code class="inline">Enum</code></a> and <a href="List.html"><code class="inline">List</code></a> can be
applied too, especially when ordering is required.</p>
</section>
<section id="summary" class="details-list">
<h1 class="section-heading">
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Summary
</h1>
<div class="summary-types summary">
<h2>
<a href="#types">Types</a>
</h2>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:key/0">key()</a>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:t/0">t()</a>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#t:t/1">t(value)</a>
</div>
</div>
<div class="summary-row">
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<a href="#t:value/0">value()</a>
</div>
</div>
</div>
<div class="summary-functions summary">
<h2>
<a href="#functions">Functions</a>
</h2>
<div class="summary-row">
<div class="summary-signature">
<a href="#delete/2">delete(keywords, key)</a>
</div>
<div class="summary-synopsis"><p>Deletes the entries in the keyword list for a specific <code class="inline">key</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#delete/3">delete(keywords, key, value)</a>
</div>
<div class="summary-synopsis"><p>Deletes the entries in the keyword list for a <code class="inline">key</code> with <code class="inline">value</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#delete_first/2">delete_first(keywords, key)</a>
</div>
<div class="summary-synopsis"><p>Deletes the first entry in the keyword list for a specific <code class="inline">key</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#drop/2">drop(keywords, keys)</a>
</div>
<div class="summary-synopsis"><p>Drops the given keys from the keyword list</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#equal?/2">equal?(left, right)</a>
</div>
<div class="summary-synopsis"><p>Checks if two keywords are equal</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#fetch!/2">fetch!(keywords, key)</a>
</div>
<div class="summary-synopsis"><p>Fetches the value for specific <code class="inline">key</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#fetch/2">fetch(keywords, key)</a>
</div>
<div class="summary-synopsis"><p>Fetches the value for a specific <code class="inline">key</code> and returns it in a tuple</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#get/3">get(keywords, key, default \\ nil)</a>
</div>
<div class="summary-synopsis"><p>Gets the value for a specific <code class="inline">key</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#get_and_update!/3">get_and_update!(keywords, key, fun)</a>
</div>
<div class="summary-synopsis"><p>Gets the value from <code class="inline">key</code> and updates it. Raises if there is no <code class="inline">key</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#get_and_update/3">get_and_update(keywords, key, fun)</a>
</div>
<div class="summary-synopsis"><p>Gets the value from <code class="inline">key</code> and updates it, all in one pass</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#get_lazy/3">get_lazy(keywords, key, fun)</a>
</div>
<div class="summary-synopsis"><p>Gets the value for a specific <code class="inline">key</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#get_values/2">get_values(keywords, key)</a>
</div>
<div class="summary-synopsis"><p>Gets all values for a specific <code class="inline">key</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#has_key?/2">has_key?(keywords, key)</a>
</div>
<div class="summary-synopsis"><p>Returns whether a given <code class="inline">key</code> exists in the given <code class="inline">keywords</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#keys/1">keys(keywords)</a>
</div>
<div class="summary-synopsis"><p>Returns all keys from the keyword list</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#keyword?/1">keyword?(term)</a>
</div>
<div class="summary-synopsis"><p>Returns <code class="inline">true</code> if <code class="inline">term</code> is a keyword list; otherwise returns <code class="inline">false</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#merge/2">merge(keywords1, keywords2)</a>
</div>
<div class="summary-synopsis"><p>Merges two keyword lists into one</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#merge/3">merge(keywords1, keywords2, fun)</a>
</div>
<div class="summary-synopsis"><p>Merges two keyword lists into one</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#new/0">new()</a>
</div>
<div class="summary-synopsis"><p>Returns an empty keyword list, i.e. an empty list</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#new/1">new(pairs)</a>
</div>
<div class="summary-synopsis"><p>Creates a keyword from an enumerable</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#new/2">new(pairs, transform)</a>
</div>
<div class="summary-synopsis"><p>Creates a keyword from an enumerable via the transformation function</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#pop/3">pop(keywords, key, default \\ nil)</a>
</div>
<div class="summary-synopsis"><p>Returns and removes all values associated with <code class="inline">key</code> in the keyword list</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#pop_first/3">pop_first(keywords, key, default \\ nil)</a>
</div>
<div class="summary-synopsis"><p>Returns and removes the first value associated with <code class="inline">key</code> in the keyword list</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#pop_lazy/3">pop_lazy(keywords, key, fun)</a>
</div>
<div class="summary-synopsis"><p>Lazily returns and removes all values associated with <code class="inline">key</code> in the keyword list</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#put/3">put(keywords, key, value)</a>
</div>
<div class="summary-synopsis"><p>Puts the given <code class="inline">value</code> under <code class="inline">key</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#put_new/3">put_new(keywords, key, value)</a>
</div>
<div class="summary-synopsis"><p>Puts the given <code class="inline">value</code> under <code class="inline">key</code> unless the entry <code class="inline">key</code>
already exists</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#put_new_lazy/3">put_new_lazy(keywords, key, fun)</a>
</div>
<div class="summary-synopsis"><p>Evaluates <code class="inline">fun</code> and puts the result under <code class="inline">key</code>
in keyword list unless <code class="inline">key</code> is already present</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#replace!/3">replace!(keywords, key, value)</a>
</div>
<div class="summary-synopsis"><p>Alters the value stored under <code class="inline">key</code> to <code class="inline">value</code>, but only
if the entry <code class="inline">key</code> already exists in <code class="inline">keywords</code></p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#split/2">split(keywords, keys)</a>
</div>
<div class="summary-synopsis"><p>Takes all entries corresponding to the given keys and extracts them into a
separate keyword list</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#take/2">take(keywords, keys)</a>
</div>
<div class="summary-synopsis"><p>Takes all entries corresponding to the given keys and returns them in a new
keyword list</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#to_list/1">to_list(keyword)</a>
</div>
<div class="summary-synopsis"><p>Returns the keyword list itself</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#update!/3">update!(keywords, key, fun)</a>
</div>
<div class="summary-synopsis"><p>Updates the <code class="inline">key</code> with the given function</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#update/4">update(keywords, key, initial, fun)</a>
</div>
<div class="summary-synopsis"><p>Updates the <code class="inline">key</code> in <code class="inline">keywords</code> with the given function</p>
</div>
</div>
<div class="summary-row">
<div class="summary-signature">
<a href="#values/1">values(keywords)</a>
</div>
<div class="summary-synopsis"><p>Returns all values from the keyword list</p>
</div>
</div>
</div>
</section>
<section id="types" class="details-list">
<h1 class="section-heading">
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Types
</h1>
<div class="types-list">
<div class="detail" id="t:key/0">
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<span class="signature">key()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L71" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>key() :: <a href="typespecs.html#basic-types">atom</a>()</pre>
</div>
</div>
<section class="docstring">
</section>
</div>
<div class="detail" id="t:t/0">
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<span class="signature">t()</span>
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<div class="specs">
<pre>t() :: [{<a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()}]</pre>
</div>
</div>
<section class="docstring">
</section>
</div>
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<span class="signature">t(value)</span>
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<div class="specs">
<pre>t(value) :: [{<a href="#t:key/0">key</a>(), value}]</pre>
</div>
</div>
<section class="docstring">
</section>
</div>
<div class="detail" id="t:value/0">
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<span class="signature">value()</span>
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<div class="specs">
<pre>value() :: <a href="typespecs.html#basic-types">any</a>()</pre>
</div>
</div>
<section class="docstring">
</section>
</div>
</div>
</section>
<section id="functions" class="details-list">
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Functions
</h1>
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<span class="signature">delete(keywords, key)</span>
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</a>
<div class="specs">
<pre>delete(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>()) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Deletes the entries in the keyword list for a specific <code class="inline">key</code>.</p>
<p>If the <code class="inline">key</code> does not exist, returns the keyword list unchanged.
Use <a href="#delete_first/2"><code class="inline">delete_first/2</code></a> to delete just the first entry in case of
duplicated keys.</p>
<h2 id="delete/2-examples" class="section-heading">
<a href="#delete/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">delete</span><span class="p" data-group-id="6119416155-1">(</span><span class="p" data-group-id="6119416155-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6119416155-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="6119416155-1">)</span><span class="w">
</span><span class="p" data-group-id="6119416155-3">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6119416155-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">delete</span><span class="p" data-group-id="6119416155-4">(</span><span class="p" data-group-id="6119416155-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="6119416155-5">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="6119416155-4">)</span><span class="w">
</span><span class="p" data-group-id="6119416155-6">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6119416155-6">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">delete</span><span class="p" data-group-id="6119416155-7">(</span><span class="p" data-group-id="6119416155-8">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6119416155-8">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="6119416155-7">)</span><span class="w">
</span><span class="p" data-group-id="6119416155-9">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6119416155-9">]</span></code></pre>
</section>
</div>
<div class="detail" id="delete/3">
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<span class="signature">delete(keywords, key, value)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L467" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>delete(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Deletes the entries in the keyword list for a <code class="inline">key</code> with <code class="inline">value</code>.</p>
<p>If no <code class="inline">key</code> with <code class="inline">value</code> exists, returns the keyword list unchanged.</p>
<h2 id="delete/3-examples" class="section-heading">
<a href="#delete/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">delete</span><span class="p" data-group-id="7214101635-1">(</span><span class="p" data-group-id="7214101635-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="7214101635-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="7214101635-1">)</span><span class="w">
</span><span class="p" data-group-id="7214101635-3">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="7214101635-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">delete</span><span class="p" data-group-id="7214101635-4">(</span><span class="p" data-group-id="7214101635-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="7214101635-5">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="7214101635-4">)</span><span class="w">
</span><span class="p" data-group-id="7214101635-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="7214101635-6">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">delete</span><span class="p" data-group-id="7214101635-7">(</span><span class="p" data-group-id="7214101635-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="7214101635-8">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="7214101635-7">)</span><span class="w">
</span><span class="p" data-group-id="7214101635-9">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="7214101635-9">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">delete</span><span class="p" data-group-id="7214101635-10">(</span><span class="p" data-group-id="7214101635-11">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="7214101635-11">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="7214101635-10">)</span><span class="w">
</span><span class="p" data-group-id="7214101635-12">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="7214101635-12">]</span></code></pre>
</section>
</div>
<div class="detail" id="delete_first/2">
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<a href="#delete_first/2" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
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</a>
<span class="signature">delete_first(keywords, key)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L538" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>delete_first(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>()) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Deletes the first entry in the keyword list for a specific <code class="inline">key</code>.</p>
<p>If the <code class="inline">key</code> does not exist, returns the keyword list unchanged.</p>
<h2 id="delete_first/2-examples" class="section-heading">
<a href="#delete_first/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">delete_first</span><span class="p" data-group-id="2174488387-1">(</span><span class="p" data-group-id="2174488387-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="2174488387-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="2174488387-1">)</span><span class="w">
</span><span class="p" data-group-id="2174488387-3">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="2174488387-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">delete_first</span><span class="p" data-group-id="2174488387-4">(</span><span class="p" data-group-id="2174488387-5">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="2174488387-5">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="2174488387-4">)</span><span class="w">
</span><span class="p" data-group-id="2174488387-6">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="2174488387-6">]</span></code></pre>
</section>
</div>
<div class="detail" id="drop/2">
<div class="detail-header">
<a href="#drop/2" class="detail-link" title="Link to this function">
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</a>
<span class="signature">drop(keywords, keys)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L941" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>drop(<a href="#t:t/0">t</a>(), [<a href="#t:key/0">key</a>()]) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Drops the given keys from the keyword list.</p>
<p>Duplicated keys are preserved in the new keyword list.</p>
<h2 id="drop/2-examples" class="section-heading">
<a href="#drop/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">drop</span><span class="p" data-group-id="3889769238-1">(</span><span class="p" data-group-id="3889769238-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="3889769238-2">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="3889769238-3">[</span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="ss">:d</span><span class="p" data-group-id="3889769238-3">]</span><span class="p" data-group-id="3889769238-1">)</span><span class="w">
</span><span class="p" data-group-id="3889769238-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="3889769238-4">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">drop</span><span class="p" data-group-id="3889769238-5">(</span><span class="p" data-group-id="3889769238-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="3889769238-6">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="3889769238-7">[</span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="ss">:d</span><span class="p" data-group-id="3889769238-7">]</span><span class="p" data-group-id="3889769238-5">)</span><span class="w">
</span><span class="p" data-group-id="3889769238-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="3889769238-8">]</span></code></pre>
</section>
</div>
<div class="detail" id="equal?/2">
<div class="detail-header">
<a href="#equal?/2" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
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</a>
<span class="signature">equal?(left, right)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L677" class="view-source" rel="help" title="View Source">
<span class="icon-code" aria-hidden="true"></span>
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<div class="specs">
<pre>equal?(<a href="#t:t/0">t</a>(), <a href="#t:t/0">t</a>()) :: <a href="typespecs.html#built-in-types">boolean</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Checks if two keywords are equal.</p>
<p>Two keywords are considered to be equal if they contain
the same keys and those keys contain the same values.</p>
<h2 id="equal?/2-examples" class="section-heading">
<a href="#equal?/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">equal?</span><span class="p" data-group-id="7995079256-1">(</span><span class="p" data-group-id="7995079256-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="7995079256-2">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="7995079256-3">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="7995079256-3">]</span><span class="p" data-group-id="7995079256-1">)</span><span class="w">
</span><span class="no">true</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">equal?</span><span class="p" data-group-id="7995079256-4">(</span><span class="p" data-group-id="7995079256-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="7995079256-5">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="7995079256-6">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="7995079256-6">]</span><span class="p" data-group-id="7995079256-4">)</span><span class="w">
</span><span class="no">false</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">equal?</span><span class="p" data-group-id="7995079256-7">(</span><span class="p" data-group-id="7995079256-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="7995079256-8">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="7995079256-9">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="7995079256-9">]</span><span class="p" data-group-id="7995079256-7">)</span><span class="w">
</span><span class="no">true</span></code></pre>
</section>
</div>
<div class="detail" id="fetch!/2">
<div class="detail-header">
<a href="#fetch!/2" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
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</a>
<span class="signature">fetch!(keywords, key)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L383" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>fetch!(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>()) :: <a href="#t:value/0">value</a>() | <a href="typespecs.html#built-in-types">no_return</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Fetches the value for specific <code class="inline">key</code>.</p>
<p>If <code class="inline">key</code> does not exist, a <a href="KeyError.html"><code class="inline">KeyError</code></a> is raised.</p>
<h2 id="fetch!/2-examples" class="section-heading">
<a href="#fetch!/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">fetch!</span><span class="p" data-group-id="1426216887-1">(</span><span class="p" data-group-id="1426216887-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="1426216887-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="1426216887-1">)</span><span class="w">
</span><span class="mi">1</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">fetch!</span><span class="p" data-group-id="1426216887-3">(</span><span class="p" data-group-id="1426216887-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="1426216887-4">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="1426216887-3">)</span><span class="w">
</span><span class="gt">** (KeyError) key :b not found in: [a: 1]</span></code></pre>
</section>
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<div class="detail" id="fetch/2">
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<span class="signature">fetch(keywords, key)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L362" class="view-source" rel="help" title="View Source">
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<pre>fetch(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>()) :: {:ok, <a href="#t:value/0">value</a>()} | :error</pre>
</div>
</div>
<section class="docstring">
<p>Fetches the value for a specific <code class="inline">key</code> and returns it in a tuple.</p>
<p>If the <code class="inline">key</code> does not exist, returns <code class="inline">:error</code>.</p>
<h2 id="fetch/2-examples" class="section-heading">
<a href="#fetch/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">fetch</span><span class="p" data-group-id="3902713453-1">(</span><span class="p" data-group-id="3902713453-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="3902713453-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="3902713453-1">)</span><span class="w">
</span><span class="p" data-group-id="3902713453-3">{</span><span class="ss">:ok</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="3902713453-3">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">fetch</span><span class="p" data-group-id="3902713453-4">(</span><span class="p" data-group-id="3902713453-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="3902713453-5">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="3902713453-4">)</span><span class="w">
</span><span class="ss">:error</span></code></pre>
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<span class="signature">get(keywords, key, default \\ nil)</span>
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<pre>get(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()) :: <a href="#t:value/0">value</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Gets the value for a specific <code class="inline">key</code>.</p>
<p>If <code class="inline">key</code> does not exist, return the default value
(<code class="inline">nil</code> if no default value).</p>
<p>If duplicated entries exist, the first one is returned.
Use <a href="#get_values/2"><code class="inline">get_values/2</code></a> to retrieve all entries.</p>
<h2 id="get/3-examples" class="section-heading">
<a href="#get/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get</span><span class="p" data-group-id="0020977066-1">(</span><span class="p" data-group-id="0020977066-2">[</span><span class="p" data-group-id="0020977066-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="0020977066-1">)</span><span class="w">
</span><span class="no">nil</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get</span><span class="p" data-group-id="0020977066-3">(</span><span class="p" data-group-id="0020977066-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0020977066-4">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="0020977066-3">)</span><span class="w">
</span><span class="mi">1</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get</span><span class="p" data-group-id="0020977066-5">(</span><span class="p" data-group-id="0020977066-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0020977066-6">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="0020977066-5">)</span><span class="w">
</span><span class="no">nil</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get</span><span class="p" data-group-id="0020977066-7">(</span><span class="p" data-group-id="0020977066-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0020977066-8">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="0020977066-7">)</span><span class="w">
</span><span class="mi">3</span></code></pre>
<p>With duplicated keys:</p>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get</span><span class="p" data-group-id="2155897331-1">(</span><span class="p" data-group-id="2155897331-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="2155897331-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="2155897331-1">)</span><span class="w">
</span><span class="mi">1</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get</span><span class="p" data-group-id="2155897331-3">(</span><span class="p" data-group-id="2155897331-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="2155897331-4">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="2155897331-3">)</span><span class="w">
</span><span class="mi">3</span></code></pre>
</section>
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<span class="signature">get_and_update!(keywords, key, fun)</span>
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<pre>get_and_update!(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), (<a href="#t:value/0">value</a>() -> {get, <a href="#t:value/0">value</a>()})) ::
{get, <a href="#t:t/0">t</a>()} | <a href="typespecs.html#built-in-types">no_return</a>()
when get: <a href="typespecs.html#built-in-types">term</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Gets the value from <code class="inline">key</code> and updates it. Raises if there is no <code class="inline">key</code>.</p>
<p>This <code class="inline">fun</code> argument receives the value of <code class="inline">key</code> and must return a
two-element tuple: the “get” value (the retrieved value, which can be
operated on before being returned) and the new value to be stored under
<code class="inline">key</code>.</p>
<p>The returned value is a tuple with the “get” value returned by <code class="inline">fun</code> and a new
keyword list with the updated value under <code class="inline">key</code>.</p>
<h2 id="get_and_update!/3-examples" class="section-heading">
<a href="#get_and_update!/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_and_update!</span><span class="p" data-group-id="2645445887-1">(</span><span class="p" data-group-id="2645445887-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="2645445887-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="2645445887-3">fn</span><span class="w"> </span><span class="n">current_value</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="p" data-group-id="2645445887-4">{</span><span class="n">current_value</span><span class="p">,</span><span class="w"> </span><span class="s">"new value!"</span><span class="p" data-group-id="2645445887-4">}</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="2645445887-3">end</span><span class="p" data-group-id="2645445887-1">)</span><span class="w">
</span><span class="p" data-group-id="2645445887-5">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="2645445887-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="s">"new value!"</span><span class="p" data-group-id="2645445887-6">]</span><span class="p" data-group-id="2645445887-5">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_and_update!</span><span class="p" data-group-id="2645445887-7">(</span><span class="p" data-group-id="2645445887-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="2645445887-8">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="2645445887-9">fn</span><span class="w"> </span><span class="n">current_value</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="p" data-group-id="2645445887-10">{</span><span class="n">current_value</span><span class="p">,</span><span class="w"> </span><span class="s">"new value!"</span><span class="p" data-group-id="2645445887-10">}</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="2645445887-9">end</span><span class="p" data-group-id="2645445887-7">)</span><span class="w">
</span><span class="gt">** (KeyError) key :b not found in: [a: 1]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_and_update!</span><span class="p" data-group-id="2645445887-11">(</span><span class="p" data-group-id="2645445887-12">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="2645445887-12">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="2645445887-13">fn</span><span class="w"> </span><span class="bp">_</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="ss">:pop</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="2645445887-13">end</span><span class="p" data-group-id="2645445887-11">)</span><span class="w">
</span><span class="p" data-group-id="2645445887-14">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="2645445887-15">[</span><span class="p" data-group-id="2645445887-15">]</span><span class="p" data-group-id="2645445887-14">}</span></code></pre>
</section>
</div>
<div class="detail" id="get_and_update/3">
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<span class="signature">get_and_update(keywords, key, fun)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L261" class="view-source" rel="help" title="View Source">
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<pre>get_and_update(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), (<a href="#t:value/0">value</a>() -> {get, <a href="#t:value/0">value</a>()} | :pop)) ::
{get, <a href="#t:t/0">t</a>()}
when get: <a href="typespecs.html#built-in-types">term</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Gets the value from <code class="inline">key</code> and updates it, all in one pass.</p>
<p>This <code class="inline">fun</code> argument receives the value of <code class="inline">key</code> (or <code class="inline">nil</code> if <code class="inline">key</code>
is not present) and must return a two-element tuple: the “get” value
(the retrieved value, which can be operated on before being returned)
and the new value to be stored under <code class="inline">key</code>. The <code class="inline">fun</code> may also
return <code class="inline">:pop</code>, implying the current value shall be removed from the
keyword list and returned.</p>
<p>The returned value is a tuple with the “get” value returned by
<code class="inline">fun</code> and a new keyword list with the updated value under <code class="inline">key</code>.</p>
<h2 id="get_and_update/3-examples" class="section-heading">
<a href="#get_and_update/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_and_update</span><span class="p" data-group-id="6734249483-1">(</span><span class="p" data-group-id="6734249483-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6734249483-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="6734249483-3">fn</span><span class="w"> </span><span class="n">current_value</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="p" data-group-id="6734249483-4">{</span><span class="n">current_value</span><span class="p">,</span><span class="w"> </span><span class="s">"new value!"</span><span class="p" data-group-id="6734249483-4">}</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="6734249483-3">end</span><span class="p" data-group-id="6734249483-1">)</span><span class="w">
</span><span class="p" data-group-id="6734249483-5">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6734249483-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="s">"new value!"</span><span class="p" data-group-id="6734249483-6">]</span><span class="p" data-group-id="6734249483-5">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_and_update</span><span class="p" data-group-id="6734249483-7">(</span><span class="p" data-group-id="6734249483-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6734249483-8">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="6734249483-9">fn</span><span class="w"> </span><span class="n">current_value</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="p" data-group-id="6734249483-10">{</span><span class="n">current_value</span><span class="p">,</span><span class="w"> </span><span class="s">"new value!"</span><span class="p" data-group-id="6734249483-10">}</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="6734249483-9">end</span><span class="p" data-group-id="6734249483-7">)</span><span class="w">
</span><span class="p" data-group-id="6734249483-11">{</span><span class="no">nil</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6734249483-12">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="s">"new value!"</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6734249483-12">]</span><span class="p" data-group-id="6734249483-11">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_and_update</span><span class="p" data-group-id="6734249483-13">(</span><span class="p" data-group-id="6734249483-14">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6734249483-14">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="6734249483-15">fn</span><span class="w"> </span><span class="bp">_</span><span class="w"> </span><span class="o">-></span><span class="w"> </span><span class="ss">:pop</span><span class="w"> </span><span class="k" data-group-id="6734249483-15">end</span><span class="p" data-group-id="6734249483-13">)</span><span class="w">
</span><span class="p" data-group-id="6734249483-16">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6734249483-17">[</span><span class="p" data-group-id="6734249483-17">]</span><span class="p" data-group-id="6734249483-16">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_and_update</span><span class="p" data-group-id="6734249483-18">(</span><span class="p" data-group-id="6734249483-19">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6734249483-19">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="6734249483-20">fn</span><span class="w"> </span><span class="bp">_</span><span class="w"> </span><span class="o">-></span><span class="w"> </span><span class="ss">:pop</span><span class="w"> </span><span class="k" data-group-id="6734249483-20">end</span><span class="p" data-group-id="6734249483-18">)</span><span class="w">
</span><span class="p" data-group-id="6734249483-21">{</span><span class="no">nil</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6734249483-22">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6734249483-22">]</span><span class="p" data-group-id="6734249483-21">}</span></code></pre>
</section>
</div>
<div class="detail" id="get_lazy/3">
<div class="detail-header">
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<span class="signature">get_lazy(keywords, key, fun)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L220" class="view-source" rel="help" title="View Source">
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<pre>get_lazy(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), (() -> <a href="#t:value/0">value</a>())) :: <a href="#t:value/0">value</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Gets the value for a specific <code class="inline">key</code>.</p>
<p>If <code class="inline">key</code> does not exist, lazily evaluates <code class="inline">fun</code> and returns its result.</p>
<p>This is useful if the default value is very expensive to calculate or
generally difficult to setup and teardown again.</p>
<p>If duplicated entries exist, the first one is returned.
Use <a href="#get_values/2"><code class="inline">get_values/2</code></a> to retrieve all entries.</p>
<h2 id="get_lazy/3-examples" class="section-heading">
<a href="#get_lazy/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="n">keyword</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p" data-group-id="8740445095-1">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="8740445095-1">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="n">fun</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k" data-group-id="8740445095-2">fn</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="c1"># some expensive operation here</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="mi">13</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="8740445095-2">end</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_lazy</span><span class="p" data-group-id="8740445095-3">(</span><span class="n">keyword</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="n">fun</span><span class="p" data-group-id="8740445095-3">)</span><span class="w">
</span><span class="mi">1</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_lazy</span><span class="p" data-group-id="8740445095-4">(</span><span class="n">keyword</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="n">fun</span><span class="p" data-group-id="8740445095-4">)</span><span class="w">
</span><span class="mi">13</span></code></pre>
</section>
</div>
<div class="detail" id="get_values/2">
<div class="detail-header">
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<span class="icon-link" aria-hidden="true"></span>
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<span class="signature">get_values(keywords, key)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L404" class="view-source" rel="help" title="View Source">
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<pre>get_values(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>()) :: [<a href="#t:value/0">value</a>()]</pre>
</div>
</div>
<section class="docstring">
<p>Gets all values for a specific <code class="inline">key</code>.</p>
<h2 id="get_values/2-examples" class="section-heading">
<a href="#get_values/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_values</span><span class="p" data-group-id="4346288845-1">(</span><span class="p" data-group-id="4346288845-2">[</span><span class="p" data-group-id="4346288845-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="4346288845-1">)</span><span class="w">
</span><span class="p" data-group-id="4346288845-3">[</span><span class="p" data-group-id="4346288845-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_values</span><span class="p" data-group-id="4346288845-4">(</span><span class="p" data-group-id="4346288845-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="4346288845-5">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="4346288845-4">)</span><span class="w">
</span><span class="p" data-group-id="4346288845-6">[</span><span class="mi">1</span><span class="p" data-group-id="4346288845-6">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">get_values</span><span class="p" data-group-id="4346288845-7">(</span><span class="p" data-group-id="4346288845-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="4346288845-8">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="4346288845-7">)</span><span class="w">
</span><span class="p" data-group-id="4346288845-9">[</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="4346288845-9">]</span></code></pre>
</section>
</div>
<div class="detail" id="has_key?/2">
<div class="detail-header">
<a href="#has_key?/2" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
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<span class="signature">has_key?(keywords, key)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L803" class="view-source" rel="help" title="View Source">
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<pre>has_key?(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>()) :: <a href="typespecs.html#built-in-types">boolean</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Returns whether a given <code class="inline">key</code> exists in the given <code class="inline">keywords</code>.</p>
<h2 id="has_key?/2-examples" class="section-heading">
<a href="#has_key?/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">has_key?</span><span class="p" data-group-id="1291992844-1">(</span><span class="p" data-group-id="1291992844-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="1291992844-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="1291992844-1">)</span><span class="w">
</span><span class="no">true</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">has_key?</span><span class="p" data-group-id="1291992844-3">(</span><span class="p" data-group-id="1291992844-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="1291992844-4">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="1291992844-3">)</span><span class="w">
</span><span class="no">false</span></code></pre>
</section>
</div>
<div class="detail" id="keys/1">
<div class="detail-header">
<a href="#keys/1" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
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<span class="signature">keys(keywords)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L427" class="view-source" rel="help" title="View Source">
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<pre>keys(<a href="#t:t/0">t</a>()) :: [<a href="#t:key/0">key</a>()]</pre>
</div>
</div>
<section class="docstring">
<p>Returns all keys from the keyword list.</p>
<p>Duplicated keys appear duplicated in the final list of keys.</p>
<h2 id="keys/1-examples" class="section-heading">
<a href="#keys/1-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="3859845519-1">(</span><span class="p" data-group-id="3859845519-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3859845519-2">]</span><span class="p" data-group-id="3859845519-1">)</span><span class="w">
</span><span class="p" data-group-id="3859845519-3">[</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="3859845519-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">keys</span><span class="p" data-group-id="3859845519-4">(</span><span class="p" data-group-id="3859845519-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="3859845519-5">]</span><span class="p" data-group-id="3859845519-4">)</span><span class="w">
</span><span class="p" data-group-id="3859845519-6">[</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="3859845519-6">]</span></code></pre>
</section>
</div>
<div class="detail" id="keyword?/1">
<div class="detail-header">
<a href="#keyword?/1" class="detail-link" title="Link to this function">
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<span class="signature">keyword?(term)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L101" class="view-source" rel="help" title="View Source">
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<pre>keyword?(<a href="typespecs.html#built-in-types">term</a>()) :: <a href="typespecs.html#built-in-types">boolean</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Returns <code class="inline">true</code> if <code class="inline">term</code> is a keyword list; otherwise returns <code class="inline">false</code>.</p>
<h2 id="keyword?/1-examples" class="section-heading">
<a href="#keyword?/1-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">keyword?</span><span class="p" data-group-id="0779329831-1">(</span><span class="p" data-group-id="0779329831-2">[</span><span class="p" data-group-id="0779329831-2">]</span><span class="p" data-group-id="0779329831-1">)</span><span class="w">
</span><span class="no">true</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">keyword?</span><span class="p" data-group-id="0779329831-3">(</span><span class="p" data-group-id="0779329831-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0779329831-4">]</span><span class="p" data-group-id="0779329831-3">)</span><span class="w">
</span><span class="no">true</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">keyword?</span><span class="p" data-group-id="0779329831-5">(</span><span class="p" data-group-id="0779329831-6">[</span><span class="p" data-group-id="0779329831-7">{</span><span class="nc">Foo</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0779329831-7">}</span><span class="p" data-group-id="0779329831-6">]</span><span class="p" data-group-id="0779329831-5">)</span><span class="w">
</span><span class="no">true</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">keyword?</span><span class="p" data-group-id="0779329831-8">(</span><span class="p" data-group-id="0779329831-9">[</span><span class="p" data-group-id="0779329831-10">{</span><span class="p" data-group-id="0779329831-10">}</span><span class="p" data-group-id="0779329831-9">]</span><span class="p" data-group-id="0779329831-8">)</span><span class="w">
</span><span class="no">false</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">keyword?</span><span class="p" data-group-id="0779329831-11">(</span><span class="p" data-group-id="0779329831-12">[</span><span class="ss">:key</span><span class="p" data-group-id="0779329831-12">]</span><span class="p" data-group-id="0779329831-11">)</span><span class="w">
</span><span class="no">false</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">keyword?</span><span class="p" data-group-id="0779329831-13">(</span><span class="p" data-group-id="0779329831-14">%{</span><span class="p" data-group-id="0779329831-14">}</span><span class="p" data-group-id="0779329831-13">)</span><span class="w">
</span><span class="no">false</span></code></pre>
</section>
</div>
<div class="detail" id="merge/2">
<div class="detail-header">
<a href="#merge/2" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
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</a>
<span class="signature">merge(keywords1, keywords2)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L707" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>merge(<a href="#t:t/0">t</a>(), <a href="#t:t/0">t</a>()) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Merges two keyword lists into one.</p>
<p>All keys, including duplicated keys, given in <code class="inline">keywords2</code> will be added
to <code class="inline">keywords1</code>, overriding any existing one.</p>
<p>There are no guarantees about the order of keys in the returned keyword.</p>
<h2 id="merge/2-examples" class="section-heading">
<a href="#merge/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">merge</span><span class="p" data-group-id="3162211512-1">(</span><span class="p" data-group-id="3162211512-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3162211512-2">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="3162211512-3">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p" data-group-id="3162211512-3">]</span><span class="p" data-group-id="3162211512-1">)</span><span class="w">
</span><span class="p" data-group-id="3162211512-4">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p" data-group-id="3162211512-4">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">merge</span><span class="p" data-group-id="3162211512-5">(</span><span class="p" data-group-id="3162211512-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3162211512-6">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="3162211512-7">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="3162211512-7">]</span><span class="p" data-group-id="3162211512-5">)</span><span class="w">
</span><span class="p" data-group-id="3162211512-8">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="3162211512-8">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">merge</span><span class="p" data-group-id="3162211512-9">(</span><span class="p" data-group-id="3162211512-10">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="3162211512-10">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="3162211512-11">[</span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="3162211512-11">]</span><span class="p" data-group-id="3162211512-9">)</span><span class="w">
</span><span class="gt">** (ArgumentError) expected a keyword list as the second argument, got: [2, 3]</span></code></pre>
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<span class="signature">merge(keywords1, keywords2, fun)</span>
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<pre>merge(<a href="#t:t/0">t</a>(), <a href="#t:t/0">t</a>(), (<a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>(), <a href="#t:value/0">value</a>() -> <a href="#t:value/0">value</a>())) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Merges two keyword lists into one.</p>
<p>All keys, including duplicated keys, given in <code class="inline">keywords2</code> will be added
to <code class="inline">keywords1</code>. The given function will be invoked to solve conflicts.</p>
<p>If <code class="inline">keywords2</code> has duplicate keys, the given function will be invoked
for each matching pair in <code class="inline">keywords1</code>.</p>
<p>There are no guarantees about the order of keys in the returned keyword.</p>
<h2 id="merge/3-examples" class="section-heading">
<a href="#merge/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">merge</span><span class="p" data-group-id="9762692227-1">(</span><span class="p" data-group-id="9762692227-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="9762692227-2">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9762692227-3">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p" data-group-id="9762692227-3">]</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="9762692227-4">fn</span><span class="w"> </span><span class="c">_k</span><span class="p">,</span><span class="w"> </span><span class="n">v1</span><span class="p">,</span><span class="w"> </span><span class="n">v2</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="n">v1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">v2</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="9762692227-4">end</span><span class="p" data-group-id="9762692227-1">)</span><span class="w">
</span><span class="p" data-group-id="9762692227-5">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p" data-group-id="9762692227-5">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">merge</span><span class="p" data-group-id="9762692227-6">(</span><span class="p" data-group-id="9762692227-7">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="9762692227-7">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9762692227-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="9762692227-8">]</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="9762692227-9">fn</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="n">v1</span><span class="p">,</span><span class="w"> </span><span class="n">v2</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="n">v1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">v2</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="9762692227-9">end</span><span class="p" data-group-id="9762692227-6">)</span><span class="w">
</span><span class="p" data-group-id="9762692227-10">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="9762692227-10">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">merge</span><span class="p" data-group-id="9762692227-11">(</span><span class="p" data-group-id="9762692227-12">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="9762692227-12">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9762692227-13">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="9762692227-13">]</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="9762692227-14">fn</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="n">v1</span><span class="p">,</span><span class="w"> </span><span class="n">v2</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="n">v1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">v2</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="9762692227-14">end</span><span class="p" data-group-id="9762692227-11">)</span><span class="w">
</span><span class="p" data-group-id="9762692227-15">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="ss">d</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">8</span><span class="p" data-group-id="9762692227-15">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">merge</span><span class="p" data-group-id="9762692227-16">(</span><span class="p" data-group-id="9762692227-17">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="9762692227-17">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="9762692227-18">[</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="9762692227-18">]</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="9762692227-19">fn</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="n">v1</span><span class="p">,</span><span class="w"> </span><span class="n">v2</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="n">v1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">v2</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="9762692227-19">end</span><span class="p" data-group-id="9762692227-16">)</span><span class="w">
</span><span class="gt">** (ArgumentError) expected a keyword list as the second argument, got: [:a, :b]</span></code></pre>
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<span class="signature">new()</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L113" class="view-source" rel="help" title="View Source">
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<pre>new() :: []</pre>
</div>
</div>
<section class="docstring">
<p>Returns an empty keyword list, i.e. an empty list.</p>
<h2 id="new/0-examples" class="section-heading">
<a href="#new/0-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">new</span><span class="p" data-group-id="1762711822-1">(</span><span class="p" data-group-id="1762711822-1">)</span><span class="w">
</span><span class="p" data-group-id="1762711822-2">[</span><span class="p" data-group-id="1762711822-2">]</span></code></pre>
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<span class="signature">new(pairs)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L132" class="view-source" rel="help" title="View Source">
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<pre>new(<a href="Enum.html#t:t/0">Enum.t</a>()) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Creates a keyword from an enumerable.</p>
<p>Duplicated entries are removed, the latest one prevails.
Unlike <code class="inline">Enum.into(enumerable, [])</code>, <code class="inline">Keyword.new(enumerable)</code>
guarantees the keys are unique.</p>
<h2 id="new/1-examples" class="section-heading">
<a href="#new/1-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">new</span><span class="p" data-group-id="4344614556-1">(</span><span class="p" data-group-id="4344614556-2">[</span><span class="p" data-group-id="4344614556-3">{</span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="4344614556-3">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="4344614556-4">{</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="4344614556-4">}</span><span class="p" data-group-id="4344614556-2">]</span><span class="p" data-group-id="4344614556-1">)</span><span class="w">
</span><span class="p" data-group-id="4344614556-5">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="4344614556-5">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">new</span><span class="p" data-group-id="4344614556-6">(</span><span class="p" data-group-id="4344614556-7">[</span><span class="p" data-group-id="4344614556-8">{</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="4344614556-8">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="4344614556-9">{</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="4344614556-9">}</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="4344614556-10">{</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="4344614556-10">}</span><span class="p" data-group-id="4344614556-7">]</span><span class="p" data-group-id="4344614556-6">)</span><span class="w">
</span><span class="p" data-group-id="4344614556-11">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="4344614556-11">]</span></code></pre>
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<span class="signature">new(pairs, transform)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L150" class="view-source" rel="help" title="View Source">
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<pre>new(<a href="Enum.html#t:t/0">Enum.t</a>(), (<a href="typespecs.html#built-in-types">term</a>() -> {<a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()})) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Creates a keyword from an enumerable via the transformation function.</p>
<p>Duplicated entries are removed, the latest one prevails.
Unlike <code class="inline">Enum.into(enumerable, [], fun)</code>,
<code class="inline">Keyword.new(enumerable, fun)</code> guarantees the keys are unique.</p>
<h2 id="new/2-examples" class="section-heading">
<a href="#new/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">new</span><span class="p" data-group-id="6955626133-1">(</span><span class="p" data-group-id="6955626133-2">[</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="6955626133-2">]</span><span class="p">,</span><span class="w"> </span><span class="k" data-group-id="6955626133-3">fn</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="o">-></span><span class="w"> </span><span class="p" data-group-id="6955626133-4">{</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="p" data-group-id="6955626133-4">}</span><span class="w"> </span><span class="k" data-group-id="6955626133-3">end</span><span class="p" data-group-id="6955626133-1">)</span><span class="w">
</span><span class="p" data-group-id="6955626133-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="6955626133-5">]</span></code></pre>
</section>
</div>
<div class="detail" id="pop/3">
<span id="pop/2"></span>
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<span class="signature">pop(keywords, key, default \\ nil)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L964" class="view-source" rel="help" title="View Source">
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<pre>pop(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()) :: {<a href="#t:value/0">value</a>(), <a href="#t:t/0">t</a>()}</pre>
</div>
</div>
<section class="docstring">
<p>Returns and removes all values associated with <code class="inline">key</code> in the keyword list.</p>
<p>All duplicated keys are removed. See <a href="#pop_first/3"><code class="inline">pop_first/3</code></a> for
removing only the first entry.</p>
<h2 id="pop/3-examples" class="section-heading">
<a href="#pop/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop</span><span class="p" data-group-id="8784100949-1">(</span><span class="p" data-group-id="8784100949-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="8784100949-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="8784100949-1">)</span><span class="w">
</span><span class="p" data-group-id="8784100949-3">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="8784100949-4">[</span><span class="p" data-group-id="8784100949-4">]</span><span class="p" data-group-id="8784100949-3">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop</span><span class="p" data-group-id="8784100949-5">(</span><span class="p" data-group-id="8784100949-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="8784100949-6">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="8784100949-5">)</span><span class="w">
</span><span class="p" data-group-id="8784100949-7">{</span><span class="no">nil</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="8784100949-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="8784100949-8">]</span><span class="p" data-group-id="8784100949-7">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop</span><span class="p" data-group-id="8784100949-9">(</span><span class="p" data-group-id="8784100949-10">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="8784100949-10">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="8784100949-9">)</span><span class="w">
</span><span class="p" data-group-id="8784100949-11">{</span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="8784100949-12">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="8784100949-12">]</span><span class="p" data-group-id="8784100949-11">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop</span><span class="p" data-group-id="8784100949-13">(</span><span class="p" data-group-id="8784100949-14">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="8784100949-14">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="8784100949-13">)</span><span class="w">
</span><span class="p" data-group-id="8784100949-15">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="8784100949-16">[</span><span class="p" data-group-id="8784100949-16">]</span><span class="p" data-group-id="8784100949-15">}</span></code></pre>
</section>
</div>
<div class="detail" id="pop_first/3">
<span id="pop_first/2"></span>
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<span class="signature">pop_first(keywords, key, default \\ nil)</span>
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<pre>pop_first(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()) :: {<a href="#t:value/0">value</a>(), <a href="#t:t/0">t</a>()}</pre>
</div>
</div>
<section class="docstring">
<p>Returns and removes the first value associated with <code class="inline">key</code> in the keyword list.</p>
<p>Duplicated keys are not removed.</p>
<h2 id="pop_first/3-examples" class="section-heading">
<a href="#pop_first/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop_first</span><span class="p" data-group-id="6215168632-1">(</span><span class="p" data-group-id="6215168632-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6215168632-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="6215168632-1">)</span><span class="w">
</span><span class="p" data-group-id="6215168632-3">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6215168632-4">[</span><span class="p" data-group-id="6215168632-4">]</span><span class="p" data-group-id="6215168632-3">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop_first</span><span class="p" data-group-id="6215168632-5">(</span><span class="p" data-group-id="6215168632-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6215168632-6">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p" data-group-id="6215168632-5">)</span><span class="w">
</span><span class="p" data-group-id="6215168632-7">{</span><span class="no">nil</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6215168632-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6215168632-8">]</span><span class="p" data-group-id="6215168632-7">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop_first</span><span class="p" data-group-id="6215168632-9">(</span><span class="p" data-group-id="6215168632-10">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6215168632-10">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="6215168632-9">)</span><span class="w">
</span><span class="p" data-group-id="6215168632-11">{</span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6215168632-12">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6215168632-12">]</span><span class="p" data-group-id="6215168632-11">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop_first</span><span class="p" data-group-id="6215168632-13">(</span><span class="p" data-group-id="6215168632-14">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6215168632-14">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p" data-group-id="6215168632-13">)</span><span class="w">
</span><span class="p" data-group-id="6215168632-15">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6215168632-16">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6215168632-16">]</span><span class="p" data-group-id="6215168632-15">}</span></code></pre>
</section>
</div>
<div class="detail" id="pop_lazy/3">
<div class="detail-header">
<a href="#pop_lazy/3" class="detail-link" title="Link to this function">
<span class="icon-link" aria-hidden="true"></span>
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</a>
<span class="signature">pop_lazy(keywords, key, fun)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L997" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>pop_lazy(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), (() -> <a href="#t:value/0">value</a>())) :: {<a href="#t:value/0">value</a>(), <a href="#t:t/0">t</a>()}</pre>
</div>
</div>
<section class="docstring">
<p>Lazily returns and removes all values associated with <code class="inline">key</code> in the keyword list.</p>
<p>This is useful if the default value is very expensive to calculate or
generally difficult to setup and teardown again.</p>
<p>All duplicated keys are removed. See <a href="#pop_first/3"><code class="inline">pop_first/3</code></a> for
removing only the first entry.</p>
<h2 id="pop_lazy/3-examples" class="section-heading">
<a href="#pop_lazy/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="n">keyword</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p" data-group-id="5412290305-1">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="5412290305-1">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="n">fun</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k" data-group-id="5412290305-2">fn</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="c1"># some expensive operation here</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="mi">13</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="5412290305-2">end</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop_lazy</span><span class="p" data-group-id="5412290305-3">(</span><span class="n">keyword</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="n">fun</span><span class="p" data-group-id="5412290305-3">)</span><span class="w">
</span><span class="p" data-group-id="5412290305-4">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="5412290305-5">[</span><span class="p" data-group-id="5412290305-5">]</span><span class="p" data-group-id="5412290305-4">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">pop_lazy</span><span class="p" data-group-id="5412290305-6">(</span><span class="n">keyword</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="n">fun</span><span class="p" data-group-id="5412290305-6">)</span><span class="w">
</span><span class="p" data-group-id="5412290305-7">{</span><span class="mi">13</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="5412290305-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="5412290305-8">]</span><span class="p" data-group-id="5412290305-7">}</span></code></pre>
</section>
</div>
<div class="detail" id="put/3">
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<span class="signature">put(keywords, key, value)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L574" class="view-source" rel="help" title="View Source">
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<div class="specs">
<pre>put(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Puts the given <code class="inline">value</code> under <code class="inline">key</code>.</p>
<p>If a previous value is already stored, all entries are
removed and the value is overridden.</p>
<h2 id="put/3-examples" class="section-heading">
<a href="#put/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">put</span><span class="p" data-group-id="5015827564-1">(</span><span class="p" data-group-id="5015827564-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="5015827564-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="5015827564-1">)</span><span class="w">
</span><span class="p" data-group-id="5015827564-3">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="5015827564-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">put</span><span class="p" data-group-id="5015827564-4">(</span><span class="p" data-group-id="5015827564-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="5015827564-5">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="5015827564-4">)</span><span class="w">
</span><span class="p" data-group-id="5015827564-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="5015827564-6">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">put</span><span class="p" data-group-id="5015827564-7">(</span><span class="p" data-group-id="5015827564-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p" data-group-id="5015827564-8">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="5015827564-7">)</span><span class="w">
</span><span class="p" data-group-id="5015827564-9">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="5015827564-9">]</span></code></pre>
</section>
</div>
<div class="detail" id="put_new/3">
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<span class="signature">put_new(keywords, key, value)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L620" class="view-source" rel="help" title="View Source">
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<pre>put_new(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Puts the given <code class="inline">value</code> under <code class="inline">key</code> unless the entry <code class="inline">key</code>
already exists.</p>
<h2 id="put_new/3-examples" class="section-heading">
<a href="#put_new/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">put_new</span><span class="p" data-group-id="0414547946-1">(</span><span class="p" data-group-id="0414547946-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0414547946-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0414547946-1">)</span><span class="w">
</span><span class="p" data-group-id="0414547946-3">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0414547946-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">put_new</span><span class="p" data-group-id="0414547946-4">(</span><span class="p" data-group-id="0414547946-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0414547946-5">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="0414547946-4">)</span><span class="w">
</span><span class="p" data-group-id="0414547946-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0414547946-6">]</span></code></pre>
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<div class="detail" id="put_new_lazy/3">
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<span class="signature">put_new_lazy(keywords, key, fun)</span>
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<pre>put_new_lazy(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), (() -> <a href="#t:value/0">value</a>())) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Evaluates <code class="inline">fun</code> and puts the result under <code class="inline">key</code>
in keyword list unless <code class="inline">key</code> is already present.</p>
<p>This is useful if the value is very expensive to calculate or
generally difficult to setup and teardown again.</p>
<h2 id="put_new_lazy/3-examples" class="section-heading">
<a href="#put_new_lazy/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="n">keyword</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p" data-group-id="1135338160-1">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="1135338160-1">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="n">fun</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k" data-group-id="1135338160-2">fn</span><span class="w"> </span><span class="o">-></span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="c1"># some expensive operation here</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="w"> </span><span class="mi">3</span><span class="w">
</span><span class="gp unselectable">...> </span><span class="k" data-group-id="1135338160-2">end</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">put_new_lazy</span><span class="p" data-group-id="1135338160-3">(</span><span class="n">keyword</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="n">fun</span><span class="p" data-group-id="1135338160-3">)</span><span class="w">
</span><span class="p" data-group-id="1135338160-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="1135338160-4">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">put_new_lazy</span><span class="p" data-group-id="1135338160-5">(</span><span class="n">keyword</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="n">fun</span><span class="p" data-group-id="1135338160-5">)</span><span class="w">
</span><span class="p" data-group-id="1135338160-6">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="1135338160-6">]</span></code></pre>
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<div class="detail" id="replace!/3">
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<span class="signature">replace!(keywords, key, value)</span>
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<span class="note">(since 1.5.0)</span>
<div class="specs">
<pre>replace!(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>()) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Alters the value stored under <code class="inline">key</code> to <code class="inline">value</code>, but only
if the entry <code class="inline">key</code> already exists in <code class="inline">keywords</code>.</p>
<p>If <code class="inline">key</code> is not present in <code class="inline">keywords</code>, a <a href="KeyError.html"><code class="inline">KeyError</code></a> exception is raised.</p>
<h2 id="replace!/3-examples" class="section-heading">
<a href="#replace!/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">replace!</span><span class="p" data-group-id="1711767421-1">(</span><span class="p" data-group-id="1711767421-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p" data-group-id="1711767421-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="1711767421-1">)</span><span class="w">
</span><span class="p" data-group-id="1711767421-3">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="1711767421-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">replace!</span><span class="p" data-group-id="1711767421-4">(</span><span class="p" data-group-id="1711767421-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="1711767421-5">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="1711767421-4">)</span><span class="w">
</span><span class="gt">** (KeyError) key :b not found in: [a: 1]</span></code></pre>
</section>
</div>
<div class="detail" id="split/2">
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<span class="signature">split(keywords, keys)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L895" class="view-source" rel="help" title="View Source">
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<pre>split(<a href="#t:t/0">t</a>(), [<a href="#t:key/0">key</a>()]) :: {<a href="#t:t/0">t</a>(), <a href="#t:t/0">t</a>()}</pre>
</div>
</div>
<section class="docstring">
<p>Takes all entries corresponding to the given keys and extracts them into a
separate keyword list.</p>
<p>Returns a tuple with the new list and the old list with removed keys.</p>
<p>Keys for which there are no entries in the keyword list are ignored.</p>
<p>Entries with duplicated keys end up in the same keyword list.</p>
<h2 id="split/2-examples" class="section-heading">
<a href="#split/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">split</span><span class="p" data-group-id="6957881553-1">(</span><span class="p" data-group-id="6957881553-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="6957881553-2">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6957881553-3">[</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="ss">:c</span><span class="p">,</span><span class="w"> </span><span class="ss">:e</span><span class="p" data-group-id="6957881553-3">]</span><span class="p" data-group-id="6957881553-1">)</span><span class="w">
</span><span class="p" data-group-id="6957881553-4">{</span><span class="p" data-group-id="6957881553-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="6957881553-5">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6957881553-6">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6957881553-6">]</span><span class="p" data-group-id="6957881553-4">}</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">split</span><span class="p" data-group-id="6957881553-7">(</span><span class="p" data-group-id="6957881553-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p" data-group-id="6957881553-8">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6957881553-9">[</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="ss">:c</span><span class="p">,</span><span class="w"> </span><span class="ss">:e</span><span class="p" data-group-id="6957881553-9">]</span><span class="p" data-group-id="6957881553-7">)</span><span class="w">
</span><span class="p" data-group-id="6957881553-10">{</span><span class="p" data-group-id="6957881553-11">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">4</span><span class="p" data-group-id="6957881553-11">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="6957881553-12">[</span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="6957881553-12">]</span><span class="p" data-group-id="6957881553-10">}</span></code></pre>
</section>
</div>
<div class="detail" id="take/2">
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<span class="signature">take(keywords, keys)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L923" class="view-source" rel="help" title="View Source">
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<pre>take(<a href="#t:t/0">t</a>(), [<a href="#t:key/0">key</a>()]) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Takes all entries corresponding to the given keys and returns them in a new
keyword list.</p>
<p>Duplicated keys are preserved in the new keyword list.</p>
<h2 id="take/2-examples" class="section-heading">
<a href="#take/2-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">take</span><span class="p" data-group-id="1817533967-1">(</span><span class="p" data-group-id="1817533967-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="1817533967-2">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="1817533967-3">[</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="ss">:c</span><span class="p">,</span><span class="w"> </span><span class="ss">:e</span><span class="p" data-group-id="1817533967-3">]</span><span class="p" data-group-id="1817533967-1">)</span><span class="w">
</span><span class="p" data-group-id="1817533967-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="1817533967-4">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">take</span><span class="p" data-group-id="1817533967-5">(</span><span class="p" data-group-id="1817533967-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="1817533967-6">]</span><span class="p">,</span><span class="w"> </span><span class="p" data-group-id="1817533967-7">[</span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="ss">:c</span><span class="p">,</span><span class="w"> </span><span class="ss">:e</span><span class="p" data-group-id="1817533967-7">]</span><span class="p" data-group-id="1817533967-5">)</span><span class="w">
</span><span class="p" data-group-id="1817533967-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">c</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">5</span><span class="p" data-group-id="1817533967-8">]</span></code></pre>
</section>
</div>
<div class="detail" id="to_list/1">
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<span class="signature">to_list(keyword)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L1043" class="view-source" rel="help" title="View Source">
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<pre>to_list(<a href="#t:t/0">t</a>()) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Returns the keyword list itself.</p>
<h2 id="to_list/1-examples" class="section-heading">
<a href="#to_list/1-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">to_list</span><span class="p" data-group-id="6477063560-1">(</span><span class="p" data-group-id="6477063560-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6477063560-2">]</span><span class="p" data-group-id="6477063560-1">)</span><span class="w">
</span><span class="p" data-group-id="6477063560-3">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="6477063560-3">]</span></code></pre>
</section>
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<div class="detail" id="update!/3">
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<span class="signature">update!(keywords, key, fun)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L827" class="view-source" rel="help" title="View Source">
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<pre>update!(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), (<a href="#t:value/0">value</a>() -> <a href="#t:value/0">value</a>())) :: <a href="#t:t/0">t</a>() | <a href="typespecs.html#built-in-types">no_return</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Updates the <code class="inline">key</code> with the given function.</p>
<p>If the <code class="inline">key</code> does not exist, raises <a href="KeyError.html"><code class="inline">KeyError</code></a>.</p>
<p>If there are duplicated keys, they are all removed and only the first one
is updated.</p>
<h2 id="update!/3-examples" class="section-heading">
<a href="#update!/3-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">update!</span><span class="p" data-group-id="3760319437-1">(</span><span class="p" data-group-id="3760319437-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="3760319437-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="p" data-group-id="3760319437-3">(</span><span class="ni">&1</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3760319437-3">)</span><span class="p" data-group-id="3760319437-1">)</span><span class="w">
</span><span class="p" data-group-id="3760319437-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3760319437-4">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">update!</span><span class="p" data-group-id="3760319437-5">(</span><span class="p" data-group-id="3760319437-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3760319437-6">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="p" data-group-id="3760319437-7">(</span><span class="ni">&1</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3760319437-7">)</span><span class="p" data-group-id="3760319437-5">)</span><span class="w">
</span><span class="p" data-group-id="3760319437-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3760319437-8">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">update!</span><span class="p" data-group-id="3760319437-9">(</span><span class="p" data-group-id="3760319437-10">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="3760319437-10">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="p" data-group-id="3760319437-11">(</span><span class="ni">&1</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="3760319437-11">)</span><span class="p" data-group-id="3760319437-9">)</span><span class="w">
</span><span class="gt">** (KeyError) key :b not found in: [a: 1]</span></code></pre>
</section>
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<div class="detail" id="update/4">
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<span class="signature">update(keywords, key, initial, fun)</span>
<a href="https://github.com/elixir-lang/elixir/blob/v1.7.2/lib/elixir/lib/keyword.ex#L872" class="view-source" rel="help" title="View Source">
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<pre>update(<a href="#t:t/0">t</a>(), <a href="#t:key/0">key</a>(), <a href="#t:value/0">value</a>(), (<a href="#t:value/0">value</a>() -> <a href="#t:value/0">value</a>())) :: <a href="#t:t/0">t</a>()</pre>
</div>
</div>
<section class="docstring">
<p>Updates the <code class="inline">key</code> in <code class="inline">keywords</code> with the given function.</p>
<p>If the <code class="inline">key</code> does not exist, inserts the given <code class="inline">initial</code> value.</p>
<p>If there are duplicated keys, they are all removed and only the first one
is updated.</p>
<h2 id="update/4-examples" class="section-heading">
<a href="#update/4-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">update</span><span class="p" data-group-id="0105519927-1">(</span><span class="p" data-group-id="0105519927-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0105519927-2">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">13</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="p" data-group-id="0105519927-3">(</span><span class="ni">&1</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0105519927-3">)</span><span class="p" data-group-id="0105519927-1">)</span><span class="w">
</span><span class="p" data-group-id="0105519927-4">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0105519927-4">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">update</span><span class="p" data-group-id="0105519927-5">(</span><span class="p" data-group-id="0105519927-6">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0105519927-6">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:a</span><span class="p">,</span><span class="w"> </span><span class="mi">13</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="p" data-group-id="0105519927-7">(</span><span class="ni">&1</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0105519927-7">)</span><span class="p" data-group-id="0105519927-5">)</span><span class="w">
</span><span class="p" data-group-id="0105519927-8">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0105519927-8">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">update</span><span class="p" data-group-id="0105519927-9">(</span><span class="p" data-group-id="0105519927-10">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p" data-group-id="0105519927-10">]</span><span class="p">,</span><span class="w"> </span><span class="ss">:b</span><span class="p">,</span><span class="w"> </span><span class="mi">11</span><span class="p">,</span><span class="w"> </span><span class="o">&</span><span class="p" data-group-id="0105519927-11">(</span><span class="ni">&1</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="0105519927-11">)</span><span class="p" data-group-id="0105519927-9">)</span><span class="w">
</span><span class="p" data-group-id="0105519927-12">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">11</span><span class="p" data-group-id="0105519927-12">]</span></code></pre>
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<div class="detail" id="values/1">
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<span class="signature">values(keywords)</span>
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<pre>values(<a href="#t:t/0">t</a>()) :: [<a href="#t:value/0">value</a>()]</pre>
</div>
</div>
<section class="docstring">
<p>Returns all values from the keyword list.</p>
<p>Values from duplicated keys will be kept in the final list of values.</p>
<h2 id="values/1-examples" class="section-heading">
<a href="#values/1-examples" class="hover-link"><span class="icon-link" aria-hidden="true"></span></a>
Examples
</h2>
<pre><code class="nohighlight makeup elixir"><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">values</span><span class="p" data-group-id="5895236813-1">(</span><span class="p" data-group-id="5895236813-2">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="5895236813-2">]</span><span class="p" data-group-id="5895236813-1">)</span><span class="w">
</span><span class="p" data-group-id="5895236813-3">[</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p" data-group-id="5895236813-3">]</span><span class="w">
</span><span class="gp unselectable">iex> </span><span class="nc">Keyword</span><span class="o">.</span><span class="n">values</span><span class="p" data-group-id="5895236813-4">(</span><span class="p" data-group-id="5895236813-5">[</span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="ss">b</span><span class="p">:</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="ss">a</span><span class="p">:</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="5895236813-5">]</span><span class="p" data-group-id="5895236813-4">)</span><span class="w">
</span><span class="p" data-group-id="5895236813-6">[</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p" data-group-id="5895236813-6">]</span></code></pre>
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