php-doc-en/reference/classobj/functions/property-exists.xml
2021-06-10 16:30:21 +03:00

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<?xml version="1.0" encoding="utf-8"?>
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<refentry xml:id="function.property-exists" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>property_exists</refname>
<refpurpose>
Checks if the object or class has a property
</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>bool</type><methodname>property_exists</methodname>
<methodparam><type class="union"><type>object</type><type>string</type></type><parameter>object_or_class</parameter></methodparam>
<methodparam><type>string</type><parameter>property</parameter></methodparam>
</methodsynopsis>
<para>
This function checks if the given <parameter>property</parameter> exists in
the specified class.
</para>
<note>
<para>
As opposed with <function>isset</function>,
<function>property_exists</function> returns &true; even if the property
has the value &null;.
</para>
</note>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>object_or_class</parameter></term>
<listitem>
<para>
The class name or an object of the class to test for
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>property</parameter></term>
<listitem>
<para>
The name of the property
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
Returns &true; if the property exists, &false; if it doesn't exist or
&null; in case of an error.
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title>A <function>property_exists</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
class myClass {
public $mine;
private $xpto;
static protected $test;
static function test() {
var_dump(property_exists('myClass', 'xpto')); //true
}
}
var_dump(property_exists('myClass', 'mine')); //true
var_dump(property_exists(new myClass, 'mine')); //true
var_dump(property_exists('myClass', 'xpto')); //true
var_dump(property_exists('myClass', 'bar')); //false
var_dump(property_exists('myClass', 'test')); //true
myClass::test();
?>
]]>
</programlisting>
</example>
</para>
</refsect1>
<refsect1 role="notes">
&reftitle.notes;
&note.uses-autoload;
<note>
<para>
The <function>property_exists</function> function cannot detect properties
that are magically accessible using the <link linkend="language.oop5.overloading.members"><literal>__get</literal></link>
magic method.
</para>
</note>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><function>method_exists</function></member>
</simplelist>
</para>
</refsect1>
</refentry>
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