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A table to clarify the difference between php is_null, empty and isset, is_nullisset_PHP tutorial

WBOY
WBOYOriginal
2016-07-13 09:47:121027browse

A table to clarify the difference between php is_null, empty and isset, is_nullisset

isset determines whether the variable already exists

empty determines whether the variable is empty or 0

is_null determines whether the variable is NULL

变量 empty is_null isset
$a=”” true false true
$a=null true true false
var $a true true false
$a=array() true false true
$a=false true false true
$a=15 false false true
$a=1 false false true
$a=0 true false true
$a=”0” true false true
$a=”true” false false true
$a=”false” false false true

www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/1028302.htmlTechArticleA table to clarify the difference between php is_null, empty and isset, is_nullisset isset determines whether the variable already exists empty determines the variable Whether it is empty or 0 is_null determines whether the variable is NULL variable...
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