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:

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:

<?php

echo (int)12.5 . '<br>'; // 12
echo (int)12.1 . '<br>'; // 12
echo (int)12.9 . '<br>'; // 12
echo (int)-12.9 . '<br>'; // -12Code language: PHP (php)

Suppose you have a string and want to cast it as an integer:

<?php 

$message = 'Hi';
$num = (int) $message;
echo $num; // 0Code 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:

<?php

$amount =  (int)'100 USD';
echo $amount; // 100Code 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:

<?php

$qty = null;
echo (int)$qty; // 0Code language: PHP (php)

Cast to a float

To cast a value to a float, you use the (float) operator. For example:

<?php

$amount = (float)100;
echo $amount; // 100Code 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:

<?php

$amount = 100;
echo (string)$amount . " USD"; // 100 USDCode 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:

<?php

$amount = 100;
echo $amount . ' USD'; // 100 USDCode language: PHP (php)

The (string) operator converts the true value to the string "1" and false value to the empty string (“”). For example:

<?php

$is_user_logged_in = true;
echo (string)$is_user_logged_in; // 1Code 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:

<?php

$numbers = [1,2,3];
$str = (string) $numbers;

echo $str; // ArrayCode 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.