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

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<refentry xml:id="function.array-slice" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>array_slice</refname>
  <refpurpose>Extract a slice of the array</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>array</type><methodname>array_slice</methodname>
   <methodparam><type>array</type><parameter>array</parameter></methodparam>
   <methodparam><type>int</type><parameter>offset</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>length</parameter><initializer>&null;</initializer></methodparam>
   <methodparam choice="opt"><type>bool</type><parameter>preserve_keys</parameter><initializer>false</initializer></methodparam>
  </methodsynopsis>
  <para>
   <function>array_slice</function> returns the sequence of elements
   from the array <parameter>array</parameter> as specified by the
   <parameter>offset</parameter> and <parameter>length</parameter>
   parameters.
  </para>
 </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>offset</parameter></term>
     <listitem>
      <para>
       If <parameter>offset</parameter> is non-negative, the sequence will
       start at that offset in the <parameter>array</parameter>.  If
       <parameter>offset</parameter> is negative, the sequence will
       start that far from the end of the <parameter>array</parameter>.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>length</parameter></term>
     <listitem>
      <para>
       If <parameter>length</parameter> is given and is positive, then
       the sequence will have up to that many elements in it. If the array
       is shorter than the <parameter>length</parameter>, then only the
       available array elements will be present. If
       <parameter>length</parameter> is given and is negative then the
       sequence will stop that many elements from the end of the
       array. If it is omitted, then the sequence will have everything
       from <parameter>offset</parameter> up until the end of the
       <parameter>array</parameter>.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>preserve_keys</parameter></term>
     <listitem>
      <para>
       Note that <function>array_slice</function> will reorder and reset the
       numeric array indices by default. You can change this behaviour by setting
       <parameter>preserve_keys</parameter> to &true;.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>
 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the slice. If the offset is larger than the size of the array then returns an empty 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>5.2.4</entry>
       <entry>
        The default value of the <parameter>length</parameter> parameter was changed to <literal>NULL</literal>. A <literal>NULL</literal> <parameter>length</parameter> now tells the function to use the length of <parameter>array</parameter>. Prior to this version, a <literal>NULL</literal> <parameter>length</parameter> was taken to mean a zero length (nothing will be returned).
       </entry>
      </row>
      <row>
       <entry>5.0.2</entry>
       <entry>
        The optional <parameter>preserve_keys</parameter> parameter was added.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>
 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>array_slice</function> examples</title>
    <programlisting role="php">
<![CDATA[
<?php
$input = array("a", "b", "c", "d", "e");

$output = array_slice($input, 2);      // returns "c", "d", and "e"
$output = array_slice($input, -2, 1);  // returns "d"
$output = array_slice($input, 0, 3);   // returns "a", "b", and "c"

// note the differences in the array keys
print_r(array_slice($input, 2, -1));
print_r(array_slice($input, 2, -1, true));
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
Array
(
    [0] => c
    [1] => d
)
Array
(
    [2] => c
    [3] => d
)
]]>
    </screen>
   </example>
  </para>
 </refsect1>
 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>array_splice</function></member>
    <member><function>unset</function></member>
    <member><function>array_chunk</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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