PHP 5.4.32 Released

array_reverse

(PHP 4, PHP 5)

array_reverseReturn an array with elements in reverse order

Description

array array_reverse ( array $array [, bool $preserve_keys = false ] )

Takes an input array and returns a new array with the order of the elements reversed.

Parameters

array

The input array.

preserve_keys

If set to TRUE numeric keys are preserved. Non-numeric keys are not affected by this setting and will always be preserved.

Return Values

Returns the reversed array.

Changelog

Version Description
4.0.3 The preserve_keys parameter was added.

Examples

Example #1 array_reverse() example

<?php
$input  
= array("php"4.0, array("green""red"));
$reversed array_reverse($input);
$preserved array_reverse($inputtrue);

print_r($input);
print_r($reversed);
print_r($preserved);
?>

The above example will output:

Array
(
    [0] => php
    [1] => 4
    [2] => Array
        (
            [0] => green
            [1] => red
        )

)
Array
(
    [0] => Array
        (
            [0] => green
            [1] => red
        )

    [1] => 4
    [2] => php
)
Array
(
    [2] => Array
        (
            [0] => green
            [1] => red
        )

    [1] => 4
    [0] => php
)

See Also

  • array_flip() - Exchanges all keys with their associated values in an array

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User Contributed Notes 3 notes

up
4
alfbennett at gmail dot com
4 years ago
Needed to just reverse keys. Don't flog me if there is a better way. This was a simple solution.

<?php
function array_reverse_keys($ar){
    return
array_reverse(array_reverse($ar,true),false);
}
?>
up
2
atulmvAThotmailDOTcoDOTuk
1 year ago
Here are a couple of routines to swap the order of two elements in an array

<?php

function array_swap_forward($arr,$elem)
{
$ndx = array_search($elem,$arr) - 1;
$b4 = array_slice($arr,0,$ndx);
$mid = array_reverse(array_slice($arr,$ndx,2));
$after = array_slice($arr,$ndx + 2);

return
array_merge($b4,$mid,$after);
}

function
array_swap_back($arr,$elem)
{
$ndx = array_search($elem,$arr);
$b4 = array_slice($arr,0,$ndx);
$mid = array_reverse(array_slice($arr,$ndx,2));
$after = array_slice($arr,$ndx + 2);

return
array_merge($b4,$mid,$after);
}

$arr =array('a','b','c','d','e','f');
print_r(array_swap_forward($arr,'c'));
echo
'<br>';
print_r(array_swap_back($arr,'c'));
?>
up
1
rahulavhad at yahoo dot com
13 years ago
This code can help in recursive reversing of the array...

<?php
$arr1
= array(2,1,array(5,2,1,array(9,8,7)),5,0);
$arr1 = array_reverse($arr1);

function
Reverse_Array($array)
{   
$index = 0;
    foreach (
$array as $subarray)
    {    if (
is_array($subarray))
        {   
$subarray = array_reverse($subarray);
           
$arr = Reverse_Array($subarray);
           
$array[$index] = $arr;
        }
        else {
$array[$index] = $subarray;}
       
$index++;
    }
    return
$array;
}

$arr2 = Reverse_Array($arr1);
?>
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