What is the difference between empty() and !?

Question

PHP

Which method is better to use for checking if a variable is empty:
if ( empty($foo) )or if ( !$foo )
And similarly, checking if a variable is not empty:
if ( !empty($foo) )or just if ( $foo )
As far as I know, using empty and just ! before the variable, they check the same thing (check for an empty string / 0 / null / false / empty array), i.e. the result is the same, but what is more relevant to use on php 7.1?

Answer 1

You are wrong, they work differently. Here you can study the table how different check methods work empty, is_null, isset, boolean, if($x) - php.net/manual/en/types.comparisons.php
What to use should be based on the logic of your code and this table.