Relevance of Two Strings

I am looking for something that would give me a comparison relevance of two strings. For eg. If I have string1 and string2, I want to compare them and see how much percentage of these two strings match against one another. Like string1 is apprx 90% equal to string2.

Something like this is what I am looking for in php. Please help.

 

<?php
// returns the percentage of the string "similarity"
function str_compare($str1, $str2) {
   $count = 0;
  
   $str1 = ereg_replace("[^a-z]", ' ', strtolower($str1));
   while(strstr($str1, '  ')) {
       $str1 = str_replace('  ', ' ', $str1);
   }
   $str1 = explode(' ', $str1);
  
   $str2 = ereg_replace("[^a-z]", ' ', strtolower($str2));
   while(strstr($str2, '  ')) {
       $str2 = str_replace('  ', ' ', $str2);
   }
   $str2 = explode(' ', $str2);
  
   if(count($str1)<count($str2)) {
       $tmp = $str1;
       $str1 = $str2;
       $str2 = $tmp;
       unset($tmp);
   }
  
   for($i=0; $i<count($str1); $i++) {
       if(in_array($str1[$i], $str2)) {
           $count++;
       }
   }
  
   return $count/count($str2)*100;
}
?>

PHP:

Taken from

http://us2.php.net/similar_text

 

Or you could just use the function itself,

$i = similar_text($first_word, $second_word, &$p);
echo("Matched: $i  Percentage: $p%");

PHP:

 

Thanks, I was not aware of this function. A green rep from me