The array_reverse() function returns an array in the reverse order. We can use the array_reverse() function to reverse the order of the array elements. It returns an array with items in reverse order.
PHP array_reverse
The array_reverse() is a built-in PHP function used to reverse the elements of an array, including the nested arrays. The array_reverse() function accepts the array as a parameter and returns the array with items in reversed order.
We can preserve the key elements according to the user’s choice.
Syntax
The syntax of array_reverse() function is following.
array_reverse(array, preserve)
Parameters
The array parameter is required, and it describes the array.
It is an optional parameter, specifying whether the function should preserve the array’s keys or not. Possible values:
- true
- false
Single Dimensional Array Reverse in PHP
To reverse a single-dimensional array in PHP, use the array_reverse() function.
See the following code.
<?php $testArray = array(11, 21, 19, 46, 29); $reverseArray = array_reverse($testArray); print_r($reverseArray);
See the output.
➜ pro php app.php
Array
(
[0] => 29
[1] => 46
[2] => 19
[3] => 21
[4] => 11
)
➜ pro
Associative Array Reverse in PHP
To reverse an associative array in PHP, use the array_reverse() function.
See the following code example.
<?php
$arr = array("Eleven"=>"Millie", "Mike"=>"Finn", "Dustin"=>"Gaten");
print_r(array_reverse($arr));
See the output.
➜ pro php app.php
Array
(
[Dustin] => Gaten
[Mike] => Finn
[Eleven] => Millie
)
➜ pro
The next program reverses an array taking the $key_preserve as FALSE by default. This doesn’t preserve the keys.
<?php
$arr = array("Netflix"=>"Marianne",
"Movie"=>"Valek",
"Bollywood"=>"Daayan");
$rev = array_reverse($arr, FALSE);
print_r($rev);
See the output.
➜ pro php app.php
Array
(
[Bollywood] => Daayan
[Movie] => Valek
[Netflix] => Marianne
)
➜ pro
Nested Array Reverse In PHP
To reverse a nested array in PHP, use the array_reverse() function.
<?php
$testArray = array(
'books' => array(
array('name' => 'Game Of Thrones', 'Author' => 'George RR Martin'),
array('name' => 'Hunger Games', 'Author' => 'Suzanne Collins'),
array('name' => 'Harry Potter', 'Author' => 'JK Rowling')
),
'movies' => array('Hunger Games', 'Harry Potter'));
$reverseArray = array_reverse($testArray);
print_r($reverseArray);
See the output.
➜ pro php app.php
Array
(
[movies] => Array
(
[0] => Hunger Games
[1] => Harry Potter
)
[books] => Array
(
[0] => Array
(
[name] => Game Of Thrones
[Author] => George RR Martin
)
[1] => Array
(
[name] => Hunger Games
[Author] => Suzanne Collins
)
[2] => Array
(
[name] => Harry Potter
[Author] => JK Rowling
)
)
)
➜ pro
Notice that a function reverses an outer array in the nested array above. However, it does not reverse the inner keys of the multidimensional array, as shown.
That’s it for this tutorial.
