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Manual: empty
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  doubleval
  Updated
Sat, 12 Aug 2000
 gettype 
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empty

(unknown)

empty -- Prüft, ob eine Variable einen Wert enthält

Beschreibung

int empty (mixed var)

Diese Funktion liefert true, wenn eine Variable nicht definiert, leer oder gleich 0 ist, ansonsten false. 


$var = 0;
if (empty ($var)) { #evaluates true 
    print '$var is either 0 or not at all set';
}
if (!isset ($var)) { // evaluates false
    print 'The $var is not set at all';
}

empty() kann nur auf Variablen, nicht aber auf Ausdrücke angewandt werden.

Siehe auch isset() und unset().


User Contributed Notes: empty

Akihiro SAGAWA <sagawa@sohgoh.net>
13-Feb-2000 11:00
This function also return true when the array is empty.
i.e.
<PRE>
&lt;?php
$foo = array();
if (empty($foo)) print "empty!!\n"; /* prints "empty!!" */
?>
</PRE>

griffon9@hotmail.com
13-Mar-2000 05:52
As of PHP4 beta 4, this function behaves differently with PHP3 and PHP4 :
$a='0';
echo(empty($a));

returns false (0) with PHP3 and true (1) with PHP4...

carl@wurb.com
14-May-2000 07:06
It should be borne in mind that the word "variable" as used in this manual generally means, not just a bare variable name like "$foo", but anything that can be assigned a value. (In other words, what in some languages is called an "lvalue".) Thus, "empty($obj->property)" and "empty($arr[12])" are valid.



strider@atlantis-tech.com
01-Jul-2000 07:16
Bone headed move guys! In php<4, if a form variable was not set in the form, empty($var) would return true. Now, empty($var) returns false.

$var = '0'; //php4 sets $var to 0 from a form even if it was not set on the form

empty($var) evaluates to TRUE in php<4
empty($var) evaluates to FALSE in php4

Argghhh!



ccjeagle@ms6.hinet.net
08-Aug-2000 09:45
php4.0.1pl2
&lt;?
$a = 0 ; print empty($a) ? "TRUE" : "FALSE"; //TRUE
$b = "0" ; print empty($b) ? "TRUE" : "FALSE"; //TRUE
$c = "" ; print empty($c) ? "TRUE" : "FALSE"; //TRUE
$d = 1 ; print empty($d) ? "TRUE" : "FALSE"; //FALSE
print empty($e) ? "TRUE" : "FALSE"; //TRUE
$f= TRUE ; print empty($f) ? "TRUE" : "FALSE"; //FALSE
$g= FALSE; print empty($g) ? "TRUE" : "FALSE"; //TRUE
$h=array();print empty($h) ? "TRUE" : "FALSE"; //TRUE
?>



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