带0和符号值的开关盒

Question

So, there's the code of switch statement:

$v1 = "String:value:0:1";
$v2 = explode(":",$v1);

switch($v2[0]) {
    case "String":
        switch($v2[2]) {
            case 0: print("v2[2] is first nul"); break;
            case "0": print("v2[2] is second (string) nul"); break;
            case 1: print("v2[2] is not nul"); break;
            case "a": print("v2[2] is NaN"); break;
        }
    break;
}

So, it should check if third part of array is 0. In case that it contains NaN-characters, I can't get it working:

• If $v2[2] is 0, then script puts out "v2[2] is first nul" (pure 0)
• If $v2[2] is not 0, it works fine
• If $v2[2] is NaN, then script puts out same as if value would be 0

What is wrong?

Thank you.

[Solved]: For not that big checks using if/then/else, in my case I decided to use case expression: case ($v2[2] === 0): print("v2[2] is second (string) nul"); break; case ($v2[2] === 0): print("v2[2] is second (string) nul"); break; .

Answer 1

See second note on http://php.net/switch :

Note that switch/case does loose comparison.

which links to http://php.net/manual/en/types.comparisons.php#types.comparisions-loose which in short means that switch compars like the == and not like the === operator.