<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Removes duplicate values from an array</title>
</head>
<body><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="function.array-uintersect.html">array_uintersect</a></div>
<div class="next" style="text-align: right; float: right;"><a href="function.array-unshift.html">array_unshift</a></div>
<div class="up"><a href="ref.array.html">Array Functions</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div><hr /><div id="function.array-unique" class="refentry">
<div class="refnamediv">
<h1 class="refname">array_unique</h1>
<p class="verinfo">(PHP 4 >= 4.0.1, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">array_unique</span> — <span class="dc-title">Removes duplicate values from an array</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.array-unique-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">array</span> <span class="methodname"><strong>array_unique</strong></span>
( <span class="methodparam"><span class="type">array</span> <code class="parameter">$array</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$sort_flags</code><span class="initializer"> = SORT_STRING</span></span>
] )</div>
<p class="para rdfs-comment">
Takes an input <code class="parameter">array</code> and returns a new array
without duplicate values.
</p>
<p class="para">
Note that keys are preserved. If multiple elements compare equal under
the given <code class="parameter">sort_flags</code>, then the key and value of
the first equal element will be retained.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>:
<span class="simpara">
Two elements are considered equal if and only if
<em>(string) $elem1 === (string) $elem2</em> i.e.
when the string representation is the same, the first element will be used.
</span>
</p></blockquote>
</div>
<div class="refsect1 parameters" id="refsect1-function.array-unique-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">array</code></dt>
<dd>
<p class="para">
The input array.
</p>
</dd>
<dt>
<code class="parameter">sort_flags</code></dt>
<dd>
<p class="para">
The optional second parameter <code class="parameter">sort_flags</code>
may be used to modify the sorting behavior using these values:
</p>
<p class="para">
Sorting type flags:
<ul class="itemizedlist">
<li class="listitem">
<span class="simpara"><strong><code>SORT_REGULAR</code></strong> - compare items normally
(don't change types)</span>
</li>
<li class="listitem">
<span class="simpara"><strong><code>SORT_NUMERIC</code></strong> - compare items numerically</span>
</li>
<li class="listitem">
<span class="simpara"><strong><code>SORT_STRING</code></strong> - compare items as strings</span>
</li>
<li class="listitem">
<span class="simpara"><strong><code>SORT_LOCALE_STRING</code></strong> - compare items as
strings, based on the current locale.
</span>
</li>
</ul>
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.array-unique-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the filtered array.
</p>
</div>
<div class="refsect1 changelog" id="refsect1-function.array-unique-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>7.2.0</td>
<td>
If <code class="parameter">sort_flags</code> is <strong><code>SORT_STRING</code></strong>,
formerly <code class="parameter">array</code> has been copied and non-unique
elements have been removed (without packing the array afterwards), but
now a new array is built by adding the unique elements. This can result
in different numeric indexes.
</td>
</tr>
<tr>
<td>5.2.10</td>
<td>
Changed the default value of <code class="parameter">sort_flags</code> back to
<strong><code>SORT_STRING</code></strong>.
</td>
</tr>
<tr>
<td>5.2.9</td>
<td>
Added the optional <code class="parameter">sort_flags</code> defaulting
to <strong><code>SORT_REGULAR</code></strong>. Prior to 5.2.9, this function used to sort
the array with <strong><code>SORT_STRING</code></strong> internally.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.array-unique-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-6209">
<p><strong>Example #1 <span class="function"><strong>array_unique()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$input </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"a" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"green"</span><span style="color: #007700">, </span><span style="color: #DD0000">"red"</span><span style="color: #007700">, </span><span style="color: #DD0000">"b" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"green"</span><span style="color: #007700">, </span><span style="color: #DD0000">"blue"</span><span style="color: #007700">, </span><span style="color: #DD0000">"red"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">array_unique</span><span style="color: #007700">(</span><span style="color: #0000BB">$input</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Array
(
[a] => green
[0] => red
[1] => blue
)
</pre></div>
</div>
</div>
</p>
<p class="para">
<div class="example" id="example-6210">
<p><strong>Example #2 <span class="function"><strong>array_unique()</strong></span> and types</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$input </span><span style="color: #007700">= array(</span><span style="color: #0000BB">4</span><span style="color: #007700">, </span><span style="color: #DD0000">"4"</span><span style="color: #007700">, </span><span style="color: #DD0000">"3"</span><span style="color: #007700">, </span><span style="color: #0000BB">4</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #DD0000">"3"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">array_unique</span><span style="color: #007700">(</span><span style="color: #0000BB">$input</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</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>
array(2) {
[0] => int(4)
[2] => string(1) "3"
}
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.array-unique-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.array-count-values.html" class="function" rel="rdfs-seeAlso">array_count_values()</a> - Counts all the values of an array</span></li>
</ul>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.array-unique-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>:
<span class="simpara">
Note that <span class="function"><strong>array_unique()</strong></span> is not intended to
work on multi dimensional arrays.
</span>
</p></blockquote>
</div>
</div><hr /><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="function.array-uintersect.html">array_uintersect</a></div>
<div class="next" style="text-align: right; float: right;"><a href="function.array-unshift.html">array_unshift</a></div>
<div class="up"><a href="ref.array.html">Array Functions</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div></body></html>
