( unknown )
הערה: isset() is a language construct.
?php $a = " test" ; $b = "anothertest" ; echo isset ($a) ; / / TRUE echo isset ($a , $b) ; / /TRUE unset ($a) ; echo isset ($a) ; / / FALSE echo isset ($a , $b) ; / /FALSE $foo = NULL ; print isset ($foo) ; / / FALSE ?
?php $a = array ( 'test ' = 1 , 'hello ' = null) ; echo isset ($a['test']) ; / / TRUE echo isset ($a['foo']) ; / / FALSE echo isset ($a['hello']) ; / / FALSE echo array_key_exists('hello' , $a) ; / / TRUE ?
See also empty( ) , unset( ) , and array_key_exists( ) .