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) {
            


        

Answer 1

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 2

I just use

$var === null and $var = -1; // since switch is not type-safe
switch ( $var ) {
    case 0:
        # this tests for zero/empty string/false
        break;
    case -1:
        # this tests for null
        break;
}

I think this still looks very readable if the comment starting with // is left behind (and the ones starting with # are probably best deleted).

Answer 3

Create an assertion-like class and put whatever logic you want in it; so long as "true" methods return $this (and nothing else to avoid false-positives.)

class Haystack
{
    public $value;

    public function __construct($value)
    {
        $this->value = $value;
    }

    public function isExactly($n)
    {
        if ($n === $this->value)
            return $this;
    }
}

$var = new Haystack(null);

switch ($var) {
    case $var->isExactly(''):
        echo "the value is an empty string";
        break;

    case $var->isExactly(null):
        echo "the value is null";
        break;
}

Or you can put your switch inside the actual class:

class Checker
{
    public $value;

    public function __construct($value)
    {
        $this->value = $value;
    }

    public function isExactly($n)
    {
        if ($n === $this->value)
            return $this;
    }

    public function contains($n)
    {
        if (strpos($this->value, $n) !== false)
            return $this;
    }

    public static function check($str)
    {
        $var = new self($str);

        switch ($var) {
            case $var->isExactly(''):
                return "'$str' is an empty string";
            case $var->isExactly(null):
                return "the value is null";
            case $var->contains('hello'):
                return "'$str' contains hello";
            default:
                return "'$str' did not meet any of your requirements.";
        }
    }
}

var_dump(Checker::check('hello world'));   # string(28) "'hello world' contains hello"

Of course that that point you might want to re-evaluate what you want to do with what you're checking and use a real validation library instead.

Answer 4

Here is your original code in a "strict" switch statement:

switch(true) {
    case $var === null:
        return 'a';
    default:
        return 'b';
}

This can also handle more complex switch statement like this:

switch(true) {
    case $var === null:
        return 'a';
    case $var === 4:
    case $var === 'foobar':
        return 'b';
    default:
        return 'c';
}

Answer 5

One of the best way is to check NULL value by using is_null

<?php
echo getValue();
function getValue()
{
    $var = 0;   
    switch(true) {
        case is_null($var) : return 'a'; break;
        default : return 'b'; break;
    }
}
?>

Answer 6

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.