Question

could anyone explain why float 0 is empty? The code below will show “weird”

$empty = (float)"0";
if($empty == "")
  echo "weird";

On the other hand if i were to the code below, it will never show “weird”.

$empty = (float)"0.01";
if($empty == "")
  echo "weird";

Answer 1

This is because in PHP the following expressions are true:

0 == ""
0.0 == ""

not because $empty here is the empty string "".

You can perform a typed equality check using ===, and these expressions will appear false, as expected:

0 === ""
0.0 === ""