PHP ||/OR In Function

Discussion in 'PHP' started by MMJ, Dec 5, 2007.

0
  1. #1
    Surprisingly enough I don't get a parse error from this:

    if (is_bool('a' || 10))
	echo 'Is boolean';
    PHP:
    This echos "Is boolean". Whats happening here?

    PHP 5.2.3
     
    MMJ, Dec 5, 2007 IP
  2. nico_swd

    nico_swd Prominent Member

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    #2
    Both values will be casted to boolean, and both would be true.

    Let's rewrite it so you understand it better.
    
$foo = 'a'; // 'a' casted to boolean is true. (bool)'a' === true
$bar = 10; // 10 casted to boolean is true too. (bool)10 === true

// When you're doing this, PHP will cast both values to boolean and operate with the given operator.
$bool = 'a' || 10; // OR: If 'a' or 10 is True - Return true

// $bool is now boolean True, so:
if (is_bool($bool))
    echo 'Is boolean';

// ... is true.. and the text is outputted.
    PHP:

    This syntax can be useful for thing like this:
    
if ($foo == 'a' OR $bar == 10)
{
    $bool = true;
}
else
{
    $bool = false;
}

// The above can be simplified to:
$bool = $foo == 'a' OR $bar == 10;

// $bool is now boolean true
    PHP:
     
    nico_swd, Dec 5, 2007 IP
    MMJ likes this.
  3. MMJ

    MMJ Guest

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    #3
    Wow, that helps. I didn't really think of it that way.

    So PHP is converting the parameter before the function looks at it. Thats what was confusing me.

    This is a bit more apparent: is_bool(('a' || 10))

    Thanks!
     
    MMJ, Dec 5, 2007 IP