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php基础急需注意的地方

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Release： 2016-06-13 13:04:38
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php基础需要注意的地方
1、empty()只能传入变量，而不能传入表达式：
empty()只能传入变量，而不能传入表达式，如果传入一个表达式，会出现内部服务器错误。同时，页面会显示一片白。

2、变量的赋值是克隆，不是引用
$a = '1';
$b = $a;
unset($a);
print $a； 
仍可以输出$a.

Related labels：
empty nbsp php print unset
source：php.cn
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