strnatcasecmp

(PHP 4, PHP 5)

strnatcasecmp --  Case insensitive string comparisons using a "natural order" algorithm

Description

int strnatcasecmp ( string str1, string str2 )

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.

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.

See also ereg(), strcasecmp(), substr(), stristr(), strcmp(), strncmp(), strncasecmp(), strnatcmp(), and strstr().


add a note add a note User Contributed Notes
thomas at uninet dot se
25-Jul-2006 03:49
There seems to be a bug in the localization for strnatcmp and strnatcasecmp. I searched the reported bugs and found a few entries which were up to four years old (but the problem still exists when using swedish characters).

These functions might work instead.
<?php
function _strnatcasecmp($left, $right) {
  return
_strnatcmp(strtolower($left), strtolower($right));
}

function
_strnatcmp($left, $right) {
  while((
strlen($left) > 0) && (strlen($right) > 0)) {
   if(
preg_match('/^([^0-9]*)([0-9].*)$/Us', $left, $lMatch)) {
    
$lTest = $lMatch[1];
    
$left = $lMatch[2];
   } else {
    
$lTest = $left;
    
$left = '';
   }
   if(
preg_match('/^([^0-9]*)([0-9].*)$/Us', $right, $rMatch)) {
    
$rTest = $rMatch[1];
    
$right = $rMatch[2];
   } else {
    
$rTest = $right;
    
$right = '';
   }
  
$test = strcmp($lTest, $rTest);
   if(
$test != 0) {
     return
$test;
   }
   if(
preg_match('/^([0-9]+)([^0-9].*)?$/Us', $left, $lMatch)) {
    
$lTest = intval($lMatch[1]);
    
$left = $lMatch[2];
   } else {
    
$lTest = 0;
   }
   if(
preg_match('/^([0-9]+)([^0-9].*)?$/Us', $right, $rMatch)) {
    
$rTest = intval($rMatch[1]);
    
$right = $rMatch[2];
   } else {
    
$rTest = 0;
   }
  
$test = $lTest - $rTest;
   if(
$test != 0) {
     return
$test;
   }
  }
  return
strcmp($left, $right);
}
?>

The code is not optimized. It was just made to solve my problem.