Alphanumeric Hyphenated Strings (Not min)

tidy-strings.php

/**
* Alphanumeric Hyphenated Strings
*/
function tidyString($string) {
  //Lower case everything
  $string = strtolower($string);
  //Make alphanumeric (removes all other characters)
  $string = preg_replace("/[^a-z0-9_\s-]/", "", $string);
  //Clean up multiple dashes or whitespaces
  $string = preg_replace("/[\s-]+/", " ", $string);
  //Convert whitespaces and underscore to dash
  $string = preg_replace("/[\s_]/", "-", $string);
  return $string;
}