php-doc-en/reference/array/functions/array-unique.xml

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.21 $ -->
<refentry xml:id="function.array-unique" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>array_unique</refname>
  <refpurpose>Removes duplicate values from an array</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>array</type><methodname>array_unique</methodname>
   <methodparam><type>array</type><parameter>array</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>sort_flags</parameter><initializer>SORT_REGULAR</initializer></methodparam>
  </methodsynopsis>
  <para>
   Takes an input <parameter>array</parameter> and returns a new array
   without duplicate values.
  </para>
  <para>
   Note that keys are preserved. <function>array_unique</function> sorts
   the values treated as string at first, then will keep the first key
   encountered for every value, and ignore all following keys. It does not
   mean that the key of the first related value from the unsorted
   <parameter>array</parameter> will be kept.
  </para>
  <note>
   <simpara>
    Two elements are considered equal if and only if
    <literal>(string) $elem1 === (string) $elem2</literal>. In words:
    when the string representation is the same.
   </simpara>
   <simpara>
    The first element will be used.
   </simpara>
  </note>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>array</parameter></term>
     <listitem>
      <para>
       The input array.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>sort_flags</parameter></term>
     <listitem>
      <para>
       The optional second parameter <parameter>sort_flags</parameter>
       may be used to modify the sorting behavior using these values:
      </para>
      <para>
       Sorting type flags:
       <itemizedlist>
        <listitem>
         <simpara><constant>SORT_REGULAR</constant> - compare items normally
         (don't change types)</simpara>
        </listitem>
        <listitem>
         <simpara><constant>SORT_NUMERIC</constant> - compare items numerically</simpara>
        </listitem>
        <listitem>
         <simpara><constant>SORT_STRING</constant> - compare items as strings</simpara>
        </listitem>
        <listitem>
         <simpara><constant>SORT_LOCALE_STRING</constant> - compare items as
          strings, based on the current locale. Added in PHP 4.4.0 and 5.0.2.
          Before PHP 6, it uses the system locale, which can be changed using
          <function>setlocale</function>. Since PHP 6, you must use the
          <function>i18n_loc_set_default</function> function.
         </simpara>
        </listitem>
       </itemizedlist>
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the filtered array.
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>5.2.9</entry>
       <entry>
        Added the optional <parameter>sort_flags</parameter>.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>array_unique</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$input = array("a" => "green", "red", "b" => "green", "blue", "red");
$result = array_unique($input);
print_r($result);
?>
]]>
    </programlisting>
    &example.outputs;
    <screen role="php">
<![CDATA[
Array
(
    [a] => green
    [0] => red
    [1] => blue
)
]]>
    </screen>
   </example>
  </para>
  <para>
   <example>
    <title><function>array_unique</function> and types</title>
    <programlisting role="php">
<![CDATA[
<?php
$input = array(4, "4", "3", 4, 3, "3");
$result = array_unique($input);
var_dump($result);
?>
]]>
    </programlisting>
    &example.outputs;
    <screen role="php">
<![CDATA[
array(2) {
  [0] => int(4)
  [2] => string(1) "3"
}
]]>
    </screen>
   </example>
  </para>
 </refsect1>

</refentry>

<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"../../../../manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->