PHP Type Casting

This tutorial will teach you about PHP type casting, which allows you to convert a value of one type to another.

Type casting is the process of converting a value of one type to another. To cast a value, use the type casting operators listed below:

Cast to an integer

The (int) type casting operator is used to convert a value to an integer.

The (int) operator is used to convert a float to an integer. It will round the result to zero. As an 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>'; // -12

Assume you have a string and want to convert it to an integer:

<?php 

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

The outcome might not be what you expected.

If a string contains numeric or leading numeric characters, the (int) function will convert it to the corresponding integer value. If not, the (int) casts the string to zero. As an example:

<?php

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

The (int) operator in this example converts the string ‘100 USD’ to an integer.

It’s worth noting that the (int) operator converts null to zero (0). As an example:

<?php

$qty = null;
echo (int)$qty; // 0

Cast to a float

The (float) operator is used to convert a value to a float. As an example:

<?php

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

Cast to a string

The (string) operator is used to convert a value to a string.

The (string) operator is used in the following example to convert the number 100 to a string:

<?php

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

In this case, you don’t need to use the (string) operator because PHP has a feature called type juggling that converts the integer to a string implicitly:

<?php

$amount = 100;
echo $amount . ' USD'; // 100 USD

True values are converted to the string “1,” while false values are converted to the empty string (“”). As an example:

<?php

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

(string) converts null to an empty string.

The (string) function converts an array to the string “Array.” As an example:

<?php

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

echo $str; // Array

You will also receive a warning that you are attempting to convert an array to a string.

Warning: Array to string conversion in …