2.6 PHP Casting

Cast to String

To cast to string, use the (string) statement:

Example 1: PHP Casting - Cast to String

$a = 5;       // Integer
$b = 5.34;    // Float
$c = "hello"; // String
$d = true;    // Boolean
$e = NULL;    // NULL

$a = (string) $a;
$b = (string) $b;
$c = (string) $c;
$d = (string) $d;
$e = (string) $e;

//To verify the type of any object in PHP, use the var_dump() function:
var_dump($a);
var_dump($b);
var_dump($c);
var_dump($d);
var_dump($e);

Cast to Integer

To cast to integer, use the (int) statement:

Example 2: PHP Casting - Cast to Integer

$a = 5;       // Integer
$b = 5.34;    // Float
$c = "25 kilometers"; // String
$d = "kilometers 25"; // String
$e = "hello"; // String
$f = true;    // Boolean
$g = NULL;    // NULL

$a = (int) $a;
$b = (int) $b;
$c = (int) $c;
$d = (int) $d;
$e = (int) $e;
$f = (int) $f;
$g = (int) $g;

Cast to Float

To cast to float, use the (float) statement:

Example 3: PHP Casting - Cast to Float

$a = 5;       // Integer
$b = 5.34;    // Float
$c = "25 kilometers"; // String
$d = "kilometers 25"; // String
$e = "hello"; // String
$f = true;    // Boolean
$g = NULL;    // NULL

$a = (float) $a;
$b = (float) $b;
$c = (float) $c;
$d = (float) $d;
$e = (float) $e;
$f = (float) $f;
$g = (float) $g;

Cast to Boolean

To cast to boolean, use the (bool) statement:

Example 4: PHP Casting - Cast to Boolean

$a = 5;       // Integer
$b = 5.34;    // Float
$c = 0;       // Integer
$d = -1;      // Integer
$e = 0.1;     // Float
$f = "hello"; // String
$g = "";      // String
$h = true;    // Boolean
$i = NULL;    // NULL

$a = (bool) $a;
$b = (bool) $b;
$c = (bool) $c;
$d = (bool) $d;
$e = (bool) $e;
$f = (bool) $f;
$g = (bool) $g;
$h = (bool) $h;
$i = (bool) $i;

• If a value is 0, NULL, false, or empty, the (bool) converts it into false, otherwise true.
• Even -1 converts to true.

Cast to Array

To cast to array, use the (array) statement:

Example 5: PHP Casting - Cast to Array part 1

$a = 5;       // Integer
$b = 5.34;    // Float
$c = "hello"; // String
$d = true;    // Boolean
$e = NULL;    // NULL

$a = (array) $a;
$b = (array) $b;
$c = (array) $c;
$d = (array) $d;
$e = (array) $e;

• When converting into arrays, most data types converts into an indexed array with one element.
• NULL values converts to an empty array object.
• Objects converts into associative arrays where the property names becomes the keys and the property values becomes the values:

Example 6: PHP Casting - Cast to Array part 2

Converting Objects into Arrays:

class Car {
  public $color;
  public $model;
  public function __construct($color, $model) {
    $this->color = $color;
    $this->model = $model;
  }
  public function message() {
    return "My car is a " . $this->color . " " . $this->model . "!";
  }
}

$myCar = new Car("red", "Volvo");

$myCar = (array) $myCar;
var_dump($myCar);

Cast to Object

To cast to object, use the (object) statement:

Example 7: PHP Casting - Cast to Object part 1

$a = 5;       // Integer
$b = 5.34;    // Float
$c = "hello"; // String
$d = true;    // Boolean
$e = NULL;    // NULL

$a = (object) $a;
$b = (object) $b;
$c = (object) $c;
$d = (object) $d;
$e = (object) $e;

• When converting into objects, most data types converts into a object with one property, named "scalar", with the corresponding value.
• NULL values converts to an empty object.
• Indexed arrays converts into objects with the index number as property name and the value as property value.
• Associative arrays converts into objects with the keys as property names and values as property values.

Example 8: PHP Casting - Cast to Object part 2

Converting Arrays into Objects:

$a = array("Volvo", "BMW", "Toyota"); // indexed array
$b = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43"); // associative array

$a = (object) $a;
$b = (object) $b;

Cast to NULL

To cast to NULL, use the (unset) statement:

Example 9: PHP Casting - Cast to NULL

$a = 5;       // Integer
$b = 5.34;    // Float
$c = "hello"; // String
$d = true;    // Boolean
$e = NULL;    // NULL

$a = (unset) $a;
$b = (unset) $b;
$c = (unset) $c;
$d = (unset) $d;
$e = (unset) $e;