Is there a difference between $str == '' and strlen($str) == 0 in PHP?

Question

As the title says: Is there a difference between $str == '' and strlen($str) == 0 in PHP? Is there any real speed difference and is one better to use than the other?

Answer 1

i find it clearer to just do "if (!$str)" .. not sure about '==' but '!' should be able to yeld better optimization techniques, as no typecasting is ever done, and is safe for strings, arrays, bools, numbers...