WeberDev.com -> PHP Manual -> String comparisons using a "natural order" algorithm

Description

int strnatcmp ( string $str1 , string $str2 )

This function implements a comparison algorithm that orders alphanumeric strings in the way a human being would, this is described as a "natural ordering". Note that this comparison is case sensitive.

Parameters

str1: The first string.
str2: The second string.

Return Values

Similar to other string comparison functions, this one returns < 0 if str1 is less than str2 ; > 0 if str1 is greater than str2 , 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 )

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

strnatcmp

Description

Parameters

Return Values

Examples

See Also