array-splice.xml

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<refentry xml:id="function.array-splice" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>array_splice</refname>
  <refpurpose>Remove a portion of the array and replace it with something else</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>array</type><methodname>array_splice</methodname>
   <methodparam><type>array</type><parameter role="reference">array</parameter></methodparam>
   <methodparam><type>int</type><parameter>offset</parameter></methodparam>
   <methodparam choice="opt"><type class="union"><type>int</type><type>null</type></type><parameter>length</parameter><initializer>&null;</initializer></methodparam>
   <methodparam choice="opt"><type>mixed</type><parameter>replacement</parameter><initializer>[]</initializer></methodparam>
  </methodsynopsis>
  <para>
   Removes the elements designated by <parameter>offset</parameter> and
   <parameter>length</parameter> from the <parameter>array</parameter> array,
   and replaces them with the elements of the
   <parameter>replacement</parameter> array, if supplied.
  </para>
  <note>
   <para>
    Numerical keys in <parameter>array</parameter> are not preserved.
   </para>
  </note>
  <note>
   <simpara>
    If <parameter>replacement</parameter> is not an array, it will be
    <link linkend="language.types.array.casting">typecast</link>
    to one (i.e. <code>(array) $replacement</code>). This may result in unexpected
    behavior when using an object or &null; <parameter>replacement</parameter>.
   </simpara>
  </note>
 </refsect1>
  <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>array</parameter></term>
     <listitem>
      <para>
       The input array.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>offset</parameter></term>
     <listitem>
      <para>
       If <parameter>offset</parameter> is positive then the start of the
       removed portion is at that offset from the beginning of the
       <parameter>array</parameter> array.
      </para>
      <para>
       If <parameter>offset</parameter> is negative then the start of the
       removed portion is at that offset from the end of the
       <parameter>array</parameter> array.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>length</parameter></term>
     <listitem>
      <para>
       If <parameter>length</parameter> is omitted, removes everything
       from <parameter>offset</parameter> to the end of the array.
      </para>
      <para>
       If <parameter>length</parameter> is specified and is positive,
       then that many elements will be removed.
      </para>
      <para>
       If <parameter>length</parameter> is specified and is negative,
       then the end of the removed portion will be that many elements
       from the end of the array.
      </para>
      <para>
       If <parameter>length</parameter> is specified and is zero,
       no elements will be removed.
      </para>
      <tip>
       <para>
        To remove everything from <parameter>offset</parameter> to the end of
        the array when <parameter>replacement</parameter> is also specified,
        use <code>count($input)</code> for <parameter>length</parameter>.
       </para>
      </tip>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>replacement</parameter></term>
     <listitem>
      <para>
       If <parameter>replacement</parameter> array is specified, then the
       removed elements are replaced with elements from this array.
      </para>
      <para>
       If <parameter>offset</parameter> and <parameter>length</parameter>
       are such that nothing is removed, then the elements from the
       <parameter>replacement</parameter> array are inserted in the place
       specified by the <parameter>offset</parameter>.
      </para>
      <note>
       <para>
        Keys in the <parameter>replacement</parameter> array are not preserved.
        </para>
      </note>
      <para>
       If <parameter>replacement</parameter> is just one element it is
       not necessary to put <literal>array()</literal> or square brackets
       around it, unless the element is an array itself, an object or &null;.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>
 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns an array consisting of the extracted elements.
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     <row>
      <entry>8.0.0</entry>
      <entry>
       <parameter>length</parameter> is nullable now.
      </entry>
     </row>
    </tbody>
   </tgroup>
  </informaltable>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>array_splice</function> examples</title>
    <programlisting role="php">
<![CDATA[
<?php
$input = array("red", "green", "blue", "yellow");
array_splice($input, 2);
var_dump($input);

$input = array("red", "green", "blue", "yellow");
array_splice($input, 1, -1);
var_dump($input);

$input = array("red", "green", "blue", "yellow");
array_splice($input, 1, count($input), "orange");
var_dump($input);

$input = array("red", "green", "blue", "yellow");
array_splice($input, -1, 1, array("black", "maroon"));
var_dump($input);
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
array(2) {
  [0]=>
  string(3) "red"
  [1]=>
  string(5) "green"
}
array(2) {
  [0]=>
  string(3) "red"
  [1]=>
  string(6) "yellow"
}
array(2) {
  [0]=>
  string(3) "red"
  [1]=>
  string(6) "orange"
}
array(5) {
  [0]=>
  string(3) "red"
  [1]=>
  string(5) "green"
  [2]=>
  string(4) "blue"
  [3]=>
  string(5) "black"
  [4]=>
  string(6) "maroon"
}
]]>
    </screen>
   </example>
  </para>
  <para>
   <example>
    <title>Equivalent statements to various <function>array_splice</function> examples</title>
    <para>
     The following statements are equivalent:
    </para>
    <programlisting role="php">
<![CDATA[
<?php

// append two elements to $input
array_push($input, $x, $y);
array_splice($input, count($input), 0, array($x, $y));

// remove the last element of $input
array_pop($input);
array_splice($input, -1);

// remove the first element of $input
array_shift($input);
array_splice($input, 0, 1);

// insert an element at the start of $input
array_unshift($input, $x, $y);
array_splice($input, 0, 0, array($x, $y));

// replace the value in $input at index $x
$input[$x] = $y; // for arrays where key equals offset
array_splice($input, $x, 1, $y);

?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>
 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>array_merge</function></member>
    <member><function>array_slice</function></member>
    <member><function>unset</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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