array_reverse() function reset the order of elements in an array in reverse order. The function takes an array as argument and return an array containing all values in reverse order. The function also reset the index of elements. To keep the indexes same we have to pass one more optional argument with values true or false.

Syntax : array_reverse(array, preserve_keys)

array : Specifies an input array.(Required)
preserve_keys : Optional parameter can be set TRUE or FALSE.(Optional)

Note :

• If value of preserve keys are set to TRUE, The function will preserve the keys. Default value is FALSE.
• Non-numeric keys are always preserved.

Example :

<?php
    $arr= array(1, 5, 7, 10, 14);  
    $arr1 = array_reverse($arr);
    $preserve = array_reverse($arr,true);    
    print_r($arr1);    
    print_r($preserve);  
?>

Output :
Array ( [0] => 14 [1] => 10 [2] => 7 [3] => 5 [4] => 1 )
Array ( [4] => 14 [3] => 10 [2] => 7 [1] => 5 [0] => 1 )