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);
      }
  }
  
?>

Added Valve to the irregular list.

Hello,
I found out that business is being transformed to busines, so I had to add it to the singular array...

I added:

'/(business)$/i' => "$1"

to the singular array

Can there be a rule for wellness, fitness, wellness etc?

Common uncountable nouns list is here: http://ieltsliz.com/uncountable-nouns-word-list/

One more adjustment please. return the same word if the word is already plural or singular.

eg. pluralize('men'); // returns 'men'
eg singularize('bag'); // returns 'bag'

Wrong plural: mongoose gives mongeese.
Right singular: mongooses gives mongoose.

It still doesn't cover the whole English language, does it?

...Em... I think ask America's President and England Queen to make all English words _s as plural / no _s as single will be more simple then do it fully by computer... As a Chinese, I insist on it 😄 .

Appreciate the effort but there are certain basic plural literature rules (other than exception list) which I expect a class like this to follow first.:

General Plural Literature Suffix Rules:

• 'ies' rule (ends in a consonant + y : baby/lady)
• 'ves' rule (ends in f or fe : leaf/knife) --- roof : rooves (correct but old english, roofs is ok).
• 'es' rule 1 (ends in a consonant + o : volcano/mango)
• 'es' rule 2 (ends in ch, sh, s, ss, x, z : match/dish/bus/glass/fox/buzz)
• 's' rule 1 (ends in a vowel + y or o : boy/radio) [Can be ignored in total]
• 's' rule 2 (ends in other than above : cat/ball)

I have a simple function gist which may outline the same.

Suggestion:
Add "police" to uncountable, otherwise Inflect::singularize('police') returns "polouse".
Could also solve by adjusting...
'/^([m|l])ice$/i' => "$1ouse",
.. but that would rule out things like "doormice" => "doormouse", "headlice" => "headlouse".

"Statuses" when converted to singular returns "Statu". How do i fix this?

Also "Addresses" returns "Addres"

Elegant solution. Thankingses

Please add all those words:

Furniture
Information
Knowledge
Jewelry
Homework
Marketing
Livestock
Education
Courage
Bravery
Luck
Cowardice
Greed
Clarity
Honesty
Evidence
Insurance
Butter
Love
News
Curiosity
Satisfaction
Work
Mud
Weather
Racism
Sexism
Patriotism
Chaos
Scenery
Help
Advice
Water
Fun
Wisdom
Silence
Sugar
Coal
Spelling
Money

plenty of words and introductory phrases for essays and data representation: https://crack-ielts.com/2021/02/06/ielts-voacbulary-and-magical-words-for-writing-task-2/
https://crack-ielts.com/2021/02/02/punch-lines-for-ielts-writing-task-2/
https://crack-ielts.com/2021/01/29/vocabulary-for-writing-task-1-in-ielts/

"octopi" is not a correct plural for octopus. It never has been, ever, in any language. Octopus is Greek, and "-i" is a Latin plural form. The correct works is "octopuses", or if you really insist on false pedantry, "octopodes".

"octopi" is not a correct plural for octopus. It never has been, ever, in any language. Octopus is Greek, and "-i" is a Latin plural form. The correct works is "octopuses", or if you really insist on false pedantry, "octopodes".

There is absolutely nothing wrong with "octopi". It was the earliest used plural and the most common for a long time. It may have originally come from a Greek word, but:

"While octopus may ultimately come from Greek it had a stay in New Latin before arriving here (in English)"

https://www.merriam-webster.com/words-at-play/the-many-plurals-of-octopus-octopi-octopuses-octopodes

Here's a bit more extensive class with more words taken into account that i created, feel free to add or suggest more:
https://github.com/rachid-aachich/php-pluralizer

Discusson on this here: https://stackoverflow.com/questions/4728933/function-switching-between-singular-and-plural/78003060?noredirect=1#comment137518517_78003060