PHP - 按名称在循环中取消设置变量

Let's say I have some variables declared - but I don't know exactly which, I just have an array with variable names.

$variable_list = array('var1', 'var2', 'var3', 'var4');

We go ahead and assign some values.

foreach($variable_list as $var_name){
$$var_name = rand(100,1000);
}

Now I want to unset these variables in a similar fashion. Not remove them from list, but unset the ACTUAL variable.

foreach($variable_list as $var_name){
unset($var_name);
}

this does not work. any ideas?

foreach($variable_list as $var_name){
unset($$var_name);
}

PHP Manual

Why do you set them using variable variables ($$var_name) and don't unset them like that? This should work:

foreach($variable_list as $var_name){
    unset($$var_name);
}

However, since you say:

Now I want to [...] not remove them from list, but unset the ACTUAL variable.

Simply use:

foreach($variable_list as $var_name){
    $$var_name = null;
}