PHP: Wrong evaluation in switch code

Question

PREAMBLE: $state can have 3 possible values:

1) 0 (zero , int)
2) 'Set Level: 10 %' (string)
3) 'Set Level: 20 %' (string)

I have a switch code that doesn't return right value.

This is the code:

<?php

$state = 0;

switch ($state) {

            case 'Set Level: 10 %':

                $return = 1;

            break;

            case 'Set Level: 20 %':

                $return = 2;

            break;

            default:

                $return = 0;

            break;

        }

        echo 'return:';

        var_dump($return);

And this is the fiddle: https://3v4l.org/IQ142

With $state = 0 it returns 1 and not 0, as default. I did try also to remove default and impose case 0: but no change.

Thank you

NOTICE: $state could be also as string. For this I need to check for string.

@MichaelBerkowski How do you know OP isn't possibly passing a string to the switch? — GrumpyCrouton, Sep 15 '17 at 17:38
@MichaelBerkowski Yes, which should default as it's not a string, but it doesn't. — GrumpyCrouton, Sep 15 '17 at 17:39
@GrumpyCrouton We are forced to assume $state is an integer since the OP doesn't state what $state is being passed in as. — clearshot66, Sep 15 '17 at 17:40
@clearshot66 Why would you assume it's an integer when the switch itself shows strings? — GrumpyCrouton, Sep 15 '17 at 17:40
Why initiate something as 0 if you don't intend it to be numeric? — clearshot66, Sep 15 '17 at 17:41
Long story short, PHP will cast strings to integers, resulting in `0` when comparing. Your input `$state` must be a string type to avoid the cast and incorrect comparison. It cannot be an int. `echo 0 == "any string"` prints 1. — Michael Berkowski, Sep 15 '17 at 17:42
@MichaelBerkowski I did add an explain. Thank you, but I need to check also the strings. — sineverba, Sep 15 '17 at 17:44
If int 0 is valid input, why not cast it to a string, make it a case, put it first and don't rely on the default? — Stefan, Sep 15 '17 at 17:45
But of course you can force a cast to string, and get the result you want: `switch ((string)$state)`. — jh1711, Sep 15 '17 at 17:45
^^ Yes. Force `$state` to be a string before allowing it to pass into the switch. That should solve this. — Michael Berkowski, Sep 15 '17 at 17:45

Leonardo · Accepted Answer · 2017-09-15T17:50:25.127

5

You can not compare an int with a string. Before sending the $state to the switch do a conversion to string. This will give you the correct result.

$state = 0;

switch((string)$state)
...

edited Sep 15 '17 at 17:50

answered Sep 15 '17 at 17:46

Leonardo

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PHP: Wrong evaluation in switch code

1 Answers1