PHP Manual
PrevNext

natsort

(PHP 4 )

natsort --  Sort an array using a "natural order" algorithm

Description

void natsort ( array array)

This function implements a sort algorithm that orders alphanumeric strings in the way a human being would. This is described as a "natural ordering". An example of the difference between this algorithm and the regular computer string sorting algorithms (used in sort()) can be seen below:

Example 1. natsort() example

<?php
$array1 = $array2 = array("img12.png", "img10.png", "img2.png", "img1.png");

sort($array1);
echo "Standard sorting\n";
print_r($array1);

natsort($array2);
echo "\nNatural order sorting\n";
print_r($array2);
?>

The code above will generate the following output: 

Standard sorting
Array
(
    [0] => img1.png
    [1] => img10.png
    [2] => img12.png
    [3] => img2.png
)

Natural order sorting
Array
(
    [3] => img1.png
    [2] => img2.png
    [1] => img10.png
    [0] => img12.png
)

For more information see: Martin Pool's Natural Order String Comparison page.

Note: If you're wanting to maintain index/value associations, consider using uasort($arr, 'strnatcmp').

See also natcasesort(), strnatcmp(), and strnatcasecmp().

PrevHomeNext
natcasesortUpnext