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<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.17 $ -->
<!-- splitted from ./en/functions/array.xml, last change in rev 1.2 -->
<refentry id="function.count">
<refnamediv>
<refname>count</refname>
<refpurpose>Count elements in an array, or properties in an object</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<methodsynopsis>
<type>int</type><methodname>count</methodname>
<methodparam><type>mixed</type><parameter>var</parameter></methodparam>
<methodparam choice="opt"><type>int</type><parameter>mode</parameter></methodparam>
</methodsynopsis>
<para>
Returns the number of elements in <parameter>var</parameter>,
which is typically an <type>array</type>, since anything else
will have one element.
</para>
<para>
For objects, if you have
<link linkend="ref.spl">SPL</link> installed, you can hook into
<function>count</function> by implementing interface
<literal>Countable</literal>. The interface has exactly one method,
<function>count</function>, which returns the return value for the
<function>count</function> function.
</para>
<para>
If <parameter>var</parameter> is not an array or an object with
implemented <literal>Countable</literal> interface,
<literal>1</literal> will be returned.
There is one exception, if <parameter>var</parameter> is &null;,
<literal>0</literal> will be returned.
</para>
<note>
<simpara>
The optional <parameter>mode</parameter> parameter is available as of
PHP 4.2.0.
</simpara>
</note>
<para>
If the optional <parameter>mode</parameter> parameter is set to
<constant>COUNT_RECURSIVE</constant> (or 1), <function>count</function>
will recursively count the array. This is particularly useful for
counting all the elements of a multidimensional array. The default
value for <parameter>mode</parameter> is <literal>0</literal>.
<function>count</function> does not detect infinite recursion.
</para>
<caution>
<para>
<function>count</function> may return 0 for a variable that
isn't set, but it may also return 0 for a variable that has
been initialized with an empty array. Use
<function>isset</function> to test if a variable is set.
</para>
</caution>
<para>
Please see the <link linkend="language.types.array">Array</link>
section of the manual for a detailed explanation of how arrays
are implemented and used in PHP.
</para>
<para>
<example>
<title><function>count</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
$a[0] = 1;
$a[1] = 3;
$a[2] = 5;
$result = count($a);
// $result == 3
$b[0] = 7;
$b[5] = 9;
$b[10] = 11;
$result = count($b);
// $result == 3
$result = count(null);
// $result == 0
$result = count(false);
// $result == 1
?>
]]>
</programlisting>
</example>
</para>
<para>
<example>
<title>
Recursive <function>count</function> example (PHP >= 4.2.0)
</title>
<programlisting role="php">
<![CDATA[
<?php
$food = array('fruits' => array('orange', 'banana', 'apple'),
'veggie' => array('carrot', 'collard', 'pea'));
// recursive count
echo count($food, COUNT_RECURSIVE); // output 8
// normal count
echo count($food); // output 2
?>
]]>
</programlisting>
</example>
</para>
<para>
See also <function>is_array</function>,
<function>isset</function>, and
<function>strlen</function>.
</para>
</refsect1>
</refentry>
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