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<title>Gets the first key of an array</title>
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<h1 class="refname">array_key_first</h1>
<p class="verinfo">(PHP 7 >= 7.3.0)</p><p class="refpurpose"><span class="refname">array_key_first</span> — <span class="dc-title">Gets the first key of an array</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.array-key-first-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><strong>array_key_first</strong></span>
( <span class="methodparam"><span class="type">array</span> <code class="parameter">$array</code></span>
)</div>
<p class="para rdfs-comment">
Get the first key of the given <code class="parameter">array</code> without affecting
the internal array pointer.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.array-key-first-parameters">
<h3 class="title">Parameters</h3>
<dl>
<dt>
<code class="parameter">array</code></dt>
<dd>
<p class="para">
An array.
</p>
</dd>
</dl>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.array-key-first-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the first key of <code class="parameter">array</code> if the array is not empty;
<strong><code>NULL</code></strong> otherwise.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.array-key-first-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-6169">
<p><strong>Example #1 Basic <span class="function"><strong>array_key_first()</strong></span> Usage</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$array </span><span style="color: #007700">= [</span><span style="color: #DD0000">'a' </span><span style="color: #007700">=> </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #DD0000">'b' </span><span style="color: #007700">=> </span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #DD0000">'c' </span><span style="color: #007700">=> </span><span style="color: #0000BB">3</span><span style="color: #007700">];<br /><br /></span><span style="color: #0000BB">$firstKey </span><span style="color: #007700">= </span><span style="color: #0000BB">array_key_first</span><span style="color: #007700">(</span><span style="color: #0000BB">$array</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">firstKey</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
string(1) "a"
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.array-key-first-seealso">
<h3 class="title">See Also</h3>
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.array-key-last.html" class="function" rel="rdfs-seeAlso">array_key_last()</a> - Gets the last key of an array</span></li>
<li class="member"><span class="function"><a href="function.reset.html" class="function" rel="rdfs-seeAlso">reset()</a> - Set the internal pointer of an array to its first element</span></li>
</ul>
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