PHP Type Casting
Summary: in this tutorial, you’ll learn about the PHP type casting that allows you to convert a value of a type to another.
Introduction to the PHP type casting
Type casting allows you to convert a value of one type to another. To cast a value, you use the following type casting operators:
| Cast Operators | Conversion |
|---|---|
| (array) | Array |
| (bool) or (boolean) | Boolean |
| (int) or (integer) | Integer |
| (object) | Object |
| (real), (double), or (float) | Float |
| (string) | String |
Let’s take some examples of using the type casting operators.
Cast to an integer
To cast a value to an integer, you use the (int) type casting operator.
The (int) operator casts a float to an integer. It’ll round the result towards zero. For example:
echo (int)12.5 . ‘<br>’; // 12
echo (int)12.1 . ‘<br>’; // 12
echo (int)12.9 . ‘<br>’; // 12
echo (int)-12.9 . ‘<br>’; // -12
Code language: PHP (php)
Suppose you have a string and want to cast it as an integer:
$message = ‘Hi’;
$num = (int) $message;
echo $num; // 0
Code language: PHP (php)
The result may not be what you expected.
If a string is numeric or leading numeric, then the (int) will cast it to the corresponding integer value. Otherwise, the (int) cast the string to zero. For example:
$amount = (int)‘100 USD’;
echo $amount; // 100
Code language: PHP (php)
In this example, the (int) operator casts the string '100 USD' as an integer.
Note that the (int) operator casts null to zero (0). For example:
$qty = null;
echo (int)$qty; // 0
Code language: PHP (php)
Cast to a float
To cast a value to a float, you use the (float) operator. For example:
$amount = (float)100;
echo $amount; // 100
Code language: PHP (php)
Cast to a string
To cast a value to a string, you use the (string) operator.
The following example uses the (string) operator to cast the number 100 to a string:
$amount = 100;
echo (string)$amount . ” USD”; // 100 USD
Code language: PHP (php)
You don’t need to use the (string) operator in this case because PHP has a feature called type juggling that implicitly converts the integer to a string:
$amount = 100;
echo $amount . ‘ USD’; // 100 USD
Code language: PHP (php)
The (string) operator converts the true value to the string "1" and false value to the empty string (“”). For example:
$is_user_logged_in = true;
echo (string)$is_user_logged_in; // 1
Code language: PHP (php)
Output:
1Code language: PHP (php)
The (string) operator casts null to an empty string.
The (string) cast an array to the "Array" string. For example:
$numbers = [1,2,3];
$str = (string) $numbers;
echo $str; // Array
Code language: PHP (php)
And you’ll get a warning that you’re attempting to convert an array to a string.
Warning: Array to string conversion in ...Code language: PHP (php)
Summary
- PHP type casting allows you to convert a value from one type to another.
- Use a type casting operator to cast a value to the desired type.