${$key}这段代码是什么意思

$globals = array($_REQUEST, $_SESSION, $_SERVER, $_FILES);foreach($globals as $global){    foreach(array_keys($global) as $key){        unset(${$key});    }}

回复讨论(解决方案)

见手册：可变变量

见手册：可变变量

$globals = array(array('param1'=>'PRC','param'=>'USA'));foreach($globals as $global){    foreach(array_keys($global) as $key){        unset(${$key});    }}

你给的例子没有多大意义，这才是惯常的用法

$a = 1;$b = 2;$c = 3;foreach(array('a', 'b', 'c') as $k) echo ${$k};

你给的例子没有多大意义，这才是惯常的用法

$a = 1;$b = 2;$c = 3;foreach(array('a', 'b', 'c') as $k) echo ${$k};