PHP array_reverse
Summary: in this tutorial, you will learn how to use the PHP array_reverse() function to reverse the order of elements in an array.
Introduction to the PHP array_reverse() function
The array_reverse() function accepts an array and returns a new array with the order of elements in the input array reversed.
The following shows the array_reverse() function:
array_reverse ( array $array , bool $preserve_keys = false ) : arrayCode language: PHP (php)
The array_reverse() function has two parameters:
- $arrayis the input array
- $preserve_keysdetermines if the numeric keys should be preserved. If- $preserve_keysis- true, the numeric key of elements in the new array will be preserved. The- $preserve_keysdoesn’t affect the non-numeric keys.
The array_reverse() doesn’t change the input array. Instead, it returns a new array.
PHP array_reverse() function examples
Let’s take some examples of using the PHP array_reverse() function.
1) Simple PHP array_reverse() function example
The following example uses the array_reverse() function to reverse the order of an array:
$numbers = [10, 20, 30];
 $reversed = array_reverse($numbers);
print_r($reversed);
 print_r($numbers);
Code language: HTML, XML (xml)
Output:
Array
 (
 [0] => 30
 [1] => 20
 [2] => 10
 )
 Array
 (
 [0] => 10
 [1] => 20
 [2] => 30
 )Code language: plaintext (plaintext)
How it works.
- First, define an array of three numbers 10, 20, 30.
- Then, use the array_reverse() function to create a new array with the order of elements in the $numbersarray reversed.
- Finally, show the reversed array and the $numbers array. As you can see, the $numbers array doesn’t change.
2) Using the PHP array_reverse() function to preserve numeric keys
The following example uses the array_reverse() function to reverse elements of an array. However, it preserves the keys of the elements:
$book = [
 'PHP Awesome',
 999,
 ['Programming', 'Web development'],
 ];
$preserved = array_reverse($book, true);
print_r($preserved);
Code language: HTML, XML (xml)
Output:
Array
 (
 [2] => Array
 (
 [0] => Programming
 [1] => Web development
 ) [1] => 999
 [0] => PHP Awesome
 )
Code language: PHP (php)
Summary
- Use the PHP array_reverse()function to reverse the order of elements in an array.
- Set the $preserve_keysto true to preserve the keys in the original array.