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# is_a

(PHP 4 >= 4.2.0, PHP 5)

is_a -- Returns `TRUE` if the object is of this class or has this class as one of its parents

## Description

bool is_a ( object object, string class_name)

This function returns `TRUE` if the object is of this class or has this class as one of its parents, `FALSE` otherwise.

示範 1.is_a() example
`<?php // define a class class WidgetFactory { var $oink = 'moo'; } // create a new object $WF = new WidgetFactory(); if (is_a($WF, 'WidgetFactory')) { echo "yes, \$WF is still a WidgetFactory\n"; } ?>`

The is_a() function is deprecated as of PHP 5 in favor of the instanceof type operator. In the above example we could use the following in PHP 5:

示範 2.Using the instanceof operator in PHP 5
`<?php if ($WF instanceof WidgetFactory) { echo 'Yes, $WF is a WidgetFactory'; } ?>`

See also get_class(), get_parent_class(), and is_subclass_of().

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