php销毁一个变量有两种方法:一种是___________,一种是____________

php销毁一个变量有两种方法:一种是___________,一种是____________

php销毁一个变量有两种方法:一种是unset(变量),一种是设置变量为空
$long="big_long_variable_name";
$$long="PHP";
$short=& $big_long_variable_name;
print "01 /$short is $short.";
print "02 Long is $big_long_variable_name.";
?>




print "03 /$short is $short";
print "04 Long is $big_long_variable_name";
?>




05 $short is PHP rocks!
06 Long is PHP rocks!




print "07 /$short is $short";
print "08 Long is $big_long_variable_name";
?>




09 $short is Programming PHP rocks!
10 Long is Programming PHP rocks!




print "11 /$short is $short";
print "12 Long is $big_long_variable_name";
?>




unset($big_long_variable_name);
print "13 /$short is $short";
print "14 Long is $big_long_variable_name.";
snow;
?>




print "15 /$short is $short.";
$short="No point TEST2 $short";
print "16 /$short is $short.";

unset掉或者给他复制给null也可以

我只知道 php 自带的一个函数 unset()

unset(变量)或设置变量为空