null Does Not Always Equal false

<?php

var_dump(null == false);

print_r([null => 1,
        false => 1,
        ]);

?>

null equals false, so the first equality is actually true.

On the other hand, using null and false as keys in an array, lead them to be cast to string: they end up being different, and that allows two elements to be stored in the array.

See Also

• null and false are in an array [Try me]

PHP Features

• index-array

• false

• null

Last updated: 14 July 2026