一张表搞清楚php is_null、empty、isset的区别,is_nullisset
Release: 2016-06-13 08:58:30
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一张表搞清楚php is_null、empty、isset的区别,is_nullisset
isset 判断变量是否已存在
empty 判断变量是否为空或为0
is_null 判断变量是否为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 |
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