strnatcasecmp()

strnatcasecmp() — Case insensitive string comparisons using a "natural order" algorithm.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

This function implements a comparison algorithm that orders alphanumeric strings in the way a human being would. The behaviour of this function is similar to strnatcmp(), except that the comparison is not case sensitive. For more information see: Martin Pool's Natural Order String Comparison page.

Signature

strnatcasecmp(string $string1, string $string2): int

Parameters

Parameter	Type	What it takes
$string1	string	The first string.
$string2	string	The second string.

Return value

Returns a value less than 0 if string1 is less than string2; a value greater than 0 if string1 is greater than string2, and 0 if they are equal. No particular meaning can be reliably inferred from the value aside from its sign.

Example

A runnable snippet:

var_dump(strnatcasecmp('Apple', 'Banana')); var_dump(strnatcasecmp('Banana', 'Apple')); var_dump(strnatcasecmp('apple', 'Apple'));

Output:

int(-1) int(1) int(0)

Changelog

Version	Change
8.2.0	This function is no longer guaranteed to return strlen($string1) - strlen($string2) when string lengths are not equal, but may now return -1 or 1 instead.