PHP strnatcasecmp() Function

Definition

The strnatcasecmp() function compares two strings in a natural way.

Syntax

PHP strnatcasecmp() Function has the following syntax.

Parameter

Return

This function returns:

• 0 - if the two strings are equal
• <0 - if string1 is less than string2
• >0 - if string1 is greater than string2

Note

In natural way, the number 2 is less than the number 10. In computer way, 10 is less than 2, because the first number in "10" is less than 2.

The strnatcasecmp() is case-insensitive.

Example 1

Compare two strings using a "natural" algorithm (case-insensitive):

<?php//  w  w w. ja v  a 2s  .c  o  m
echo strnatcasecmp("2Hello world!","10Hello WORLD!");
echo "\n";
echo strnatcasecmp("10Hello world!","2Hello WORLD!");
?>

The code above generates the following result.

Example 2

Difference between natural algorithm (strnatcmp) and regular computer string sorting algorithms (strcmp):

<?php//w ww.  j  a v a 2  s .  c om
$arr1 = $arr2 = array("PHP1","PHP2","PHP10","PHP01","PHP100","PHP20","PHP30","PHP200");
echo "Standard string comparison"."\n";
usort($arr1,"strcmp");

print_r($arr1);
echo "\n";

echo "Natural order string comparison"."\n";
usort($arr2,"strnatcmp");

print_r($arr2);
?>

The code above generates the following result.