Question

Let me share some PHP code with you:

$var1 = '';

$var2 = 0;

echo '<pre>';
var_dump($var1 == $var2); //prints bool(true)
echo '</pre>';

echo '<pre>';
var_dump($var1 != $var2); //prints bool(false)
echo '</pre>';

echo '<pre>';
var_dump(!$var1 == $var2); //prints bool(false)
echo '</pre>';

echo '---<br />';

echo '<pre>';
var_dump($var1 === $var2); //prints bool(false)
echo '</pre>';

echo '<pre>';
var_dump($var1 !== $var2); //prints bool(true)
echo '</pre>';

echo '<pre>';
var_dump(!$var1 === $var2); //prints bool(false) .. WTFF????
echo '</pre>';

Question is… why does that last statement (! $var1 === $var2) NOT yield the same result as ($var !== $var2) ??? I mean, it’s what we would expect, no?

I used to use both ways interchangeably but now I only use !== although I still don’t know why the other form does not work…

Answer 1

!$var1 is TRUE, $var2is 0.

They are not equal, so the result is false.

Maybe you were confused with !($var1 === $var2)