array_shift : Only variables should be passed by reference error in php [duplicate]

Question

I got an error: Strict Standards: Only variables should be passed by reference

 $string =  array_shift(array_keys($_REQUEST));

How can I correct that ?

Answer 1

$tmpArray = array_keys($_REQUEST);
$string =  array_shift($tmpArray);

Temporary array needed :(

Answer 2

Assign the result of array_keys($_REQUEST) to a variable and pass that variable to array_shift:

$var = array_keys($_REQUEST);
$string =  array_shift($var);

Answer 3

You might have a set up PHP to run under strict mode or it might have been the default behaviour.

Since output of array_keys($_REQUEST) is not a variable and under strict mode this will generate a warning. This behavior is extremely non-intuitive as the array_keys($_REQUEST) method returns an array value.

So to resolve this problem, assign the output of array_keys($_REQUEST) to a variable and then use it like below:

$keys = array_keys($_REQUEST);
$shift = array_shift($keys);