A PHP Class for converting English words between Singular and Plural.

Inflect.php

<?php
  
  // original source: http://kuwamoto.org/2007/12/17/improved-pluralizing-in-php-actionscript-and-ror/
  
  /*
    The MIT License (MIT)
    
    Copyright (c) 2015
    
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:
    
    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.
    
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.
  */
  
  // ORIGINAL NOTES
  //
  // Thanks to http://www.eval.ca/articles/php-pluralize (MIT license)
  //           http://dev.rubyonrails.org/browser/trunk/activesupport/lib/active_support/inflections.rb (MIT license)
  //           http://www.fortunecity.com/bally/durrus/153/gramch13.html
  //           http://www2.gsu.edu/~wwwesl/egw/crump.htm
  //
  // Changes (12/17/07)
  //   Major changes
  //   --
  //   Fixed irregular noun algorithm to use regular expressions just like the original Ruby source.
  //       (this allows for things like fireman -> firemen
  //   Fixed the order of the singular array, which was backwards.
  //
  //   Minor changes
  //   --
  //   Removed incorrect pluralization rule for /([^aeiouy]|qu)ies$/ => $1y
  //   Expanded on the list of exceptions for *o -> *oes, and removed rule for buffalo -> buffaloes
  //   Removed dangerous singularization rule for /([^f])ves$/ => $1fe
  //   Added more specific rules for singularizing lives, wives, knives, sheaves, loaves, and leaves and thieves
  //   Added exception to /(us)es$/ => $1 rule for houses => house and blouses => blouse
  //   Added excpetions for feet, geese and teeth
  //   Added rule for deer -> deer
  
  // Changes:
  //   Removed rule for virus -> viri
  //   Added rule for potato -> potatoes
  //   Added rule for *us -> *uses
  
  class Inflect
  {
      static $plural = array(
          '/(quiz)$/i'               => "$1zes",
          '/^(ox)$/i'                => "$1en",
          '/([m|l])ouse$/i'          => "$1ice",
          '/(matr|vert|ind)ix|ex$/i' => "$1ices",
          '/(x|ch|ss|sh)$/i'         => "$1es",
          '/([^aeiouy]|qu)y$/i'      => "$1ies",
          '/(hive)$/i'               => "$1s",
          '/(?:([^f])fe|([lr])f)$/i' => "$1$2ves",
          '/(shea|lea|loa|thie)f$/i' => "$1ves",
          '/sis$/i'                  => "ses",
          '/([ti])um$/i'             => "$1a",
          '/(tomat|potat|ech|her|vet)o$/i'=> "$1oes",
          '/(bu)s$/i'                => "$1ses",
          '/(alias)$/i'              => "$1es",
          '/(octop)us$/i'            => "$1i",
          '/(ax|test)is$/i'          => "$1es",
          '/(us)$/i'                 => "$1es",
          '/s$/i'                    => "s",
          '/$/'                      => "s"
      );
      
      static $singular = array(
          '/(quiz)zes$/i'             => "$1",
          '/(matr)ices$/i'            => "$1ix",
          '/(vert|ind)ices$/i'        => "$1ex",
          '/^(ox)en$/i'               => "$1",
          '/(alias)es$/i'             => "$1",
          '/(octop|vir)i$/i'          => "$1us",
          '/(cris|ax|test)es$/i'      => "$1is",
          '/(shoe)s$/i'               => "$1",
          '/(o)es$/i'                 => "$1",
          '/(bus)es$/i'               => "$1",
          '/([m|l])ice$/i'            => "$1ouse",
          '/(x|ch|ss|sh)es$/i'        => "$1",
          '/(m)ovies$/i'              => "$1ovie",
          '/(s)eries$/i'              => "$1eries",
          '/([^aeiouy]|qu)ies$/i'     => "$1y",
          '/([lr])ves$/i'             => "$1f",
          '/(tive)s$/i'               => "$1",
          '/(hive)s$/i'               => "$1",
          '/(li|wi|kni)ves$/i'        => "$1fe",
          '/(shea|loa|lea|thie)ves$/i'=> "$1f",
          '/(^analy)ses$/i'           => "$1sis",
          '/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)ses$/i'  => "$1$2sis",        
          '/([ti])a$/i'               => "$1um",
          '/(n)ews$/i'                => "$1ews",
          '/(h|bl)ouses$/i'           => "$1ouse",
          '/(corpse)s$/i'             => "$1",
          '/(us)es$/i'                => "$1",
          '/s$/i'                     => ""
      );
      
      static $irregular = array(
          'move'   => 'moves',
          'foot'   => 'feet',
          'goose'  => 'geese',
          'sex'    => 'sexes',
          'child'  => 'children',
          'man'    => 'men',
          'tooth'  => 'teeth',
          'person' => 'people',
          'valve'  => 'valves'
      );
      
      static $uncountable = array( 
          'sheep', 
          'fish',
          'deer',
          'series',
          'species',
          'money',
          'rice',
          'information',
          'equipment'
      );
      
      public static function pluralize( $string ) 
      {
          // save some time in the case that singular and plural are the same
          if ( in_array( strtolower( $string ), self::$uncountable ) )
              return $string;
              
      
          // check for irregular singular forms
          foreach ( self::$irregular as $pattern => $result )
          {
              $pattern = '/' . $pattern . '$/i';
              
              if ( preg_match( $pattern, $string ) )
                  return preg_replace( $pattern, $result, $string);
          }
          
          // check for matches using regular expressions
          foreach ( self::$plural as $pattern => $result )
          {
              if ( preg_match( $pattern, $string ) )
                  return preg_replace( $pattern, $result, $string );
          }
          
          return $string;
      }
      
      public static function singularize( $string )
      {
          // save some time in the case that singular and plural are the same
          if ( in_array( strtolower( $string ), self::$uncountable ) )
              return $string;
  
          // check for irregular plural forms
          foreach ( self::$irregular as $result => $pattern )
          {
              $pattern = '/' . $pattern . '$/i';
              
              if ( preg_match( $pattern, $string ) )
                  return preg_replace( $pattern, $result, $string);
          }
          
          // check for matches using regular expressions
          foreach ( self::$singular as $pattern => $result )
          {
              if ( preg_match( $pattern, $string ) )
                  return preg_replace( $pattern, $result, $string );
          }
          
          return $string;
      }
      
      public static function pluralize_if($count, $string)
      {
          if ($count == 1)
              return "1 $string";
          else
              return $count . " " . self::pluralize($string);
      }
  }
  
?>