PHP Types Type Casting


Example

PHP will generally correctly guess the data type you intend to use from the context it's used in, however sometimes it is useful to manually force a type. This can be accomplished by prefixing the declaration with the name of the required type in parenthesis:

$bool = true;
var_dump($bool); // bool(true)

$int = (int) true;
var_dump($int); // int(1)

$string = (string) true;
var_dump($string); // string(1) "1"
$string = (string) false;
var_dump($string); // string(0) ""

$float = (float) true;
var_dump($float); // float(1)

$array = ['x' => 'y'];
var_dump((object) $array); // object(stdClass)#1 (1) { ["x"]=> string(1) "y" } 

$object = new stdClass();
$object->x = 'y';
var_dump((array) $object); // array(1) { ["x"]=> string(1) "y" }

$string = "asdf";
var_dump((unset)$string); // NULL

But be carefull: not all type casts work as one might expect:

// below 3 statements hold for 32-bits systems (PHP_INT_MAX=2147483647)
// an integer value bigger than PHP_INT_MAX is automatically converted to float:
var_dump(       999888777666 ); // float(999888777666)
// forcing to (int) gives overflow:
var_dump((int)  999888777666 ); // int(-838602302)
// but in a string it just returns PHP_INT_MAX
var_dump((int) "999888777666"); // int(2147483647)

var_dump((bool) []);      // bool(false) (empty array)
var_dump((bool) [false]); // bool(true)  (non-empty array)