PHP strnatcmp

(PHP 4, PHP 5, PHP 7, PHP 8)

strnatcmp — String comparisons using a "natural order" algorithm

#Parameters

string1
The first string.

string2
The second string.

#Return Values

Similar to other string comparison functions, this one returns < 0 if string1 is less than string2; > 0 if string1 is greater than string2, and 0 if they are equal.

#Examples

An example of the difference between this algorithm and the regular computer string sorting algorithms (used in strcmp()) can be seen below:

<?php
$arr1 = $arr2 = array("img12.png", "img10.png", "img2.png", "img1.png");
echo "Standard string comparison\n";
usort($arr1, "strcmp");
print_r($arr1);
echo "\nNatural order string comparison\n";
usort($arr2, "strnatcmp");
print_r($arr2);
?>

The above example will output:

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

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