make switch use === comparison not == comparison In PHP

Question

Is there anyway to make it so that the following code still uses a switch and returns b not a? Thanks!

$var = 0;
switch($var) {
    case NULL : return 'a'; break;
    default : return 'b'; break;
}

Using if statements, of course, you'd do it like this:

$var = 0;
if($var === NULL) return 'a';
else return 'b';

But for more complex examples, this becomes verbose.

Answer 1

Sorry, you cannot use a === comparison in switch, since according to the switch() documentaion:

Note that switch/case does loose comparision.

This means you'll have to come up with a work around. From the loose comparisons table, you could make use of the fact that NULL == "0" is false by type casting:

<?php
$var = 0;
switch((string)$var) 
{
    case "" : echo 'a'; break; // This tests for NULL or empty string   
    default : echo 'b'; break; // Everything else, including zero
}
// Output: 'b'
?>

Live Demo

Answer 2

make switch use === comparison not == comparison In PHP

Unfortunately switch uses loose comparison and as far as I know there's no way to change that.

Answer 3

Nope. From the manual page:

Note that switch/case does loose comparision.

If you only have two conditions, use an if like your second example. Otherwise, check for NULL first and switch on the other possibilities:

if (is_null($var))
{
  return 'a';
}

switch ($var)
{
    // ...
}

Answer 4

This is not possible.

You can, however, put the if statements inside the switch:

switch($var) {
    // Loose cases here

    case 0:
        if($var === NULL) {
            return 'a';
        }

        // Fall through

    default:
        return 'b';
}

Or simply:

switch($var) {
    // Loose cases here

    default:
        if($var === NULL) {
            return 'a';
        }

        return 'b';
}

Answer 5

One way you could do this is to do what I think of as a backwards switch (there may be a more official name for it). The idea is that you put true or false at the top and then your conditionals in the case statements.

switch(true)
{
  case ($var === NULL):
    return 'a';
    break;
  case ($var === 0):
    return 'b';
    break;
  default:
    return 'c';
}

Answer 6

You can also switch on the type of the variable:

switch (gettype($var)) {
...
}