Convert singular to plural

Question

There are two forms of nouns, singular and plural. The conversion between these two is quite easy.

1. Normally, you end it with s. ex. car => cars.

2. If it ends with s,x,z,ch or sh, end it with es. ex. bus=>buses.

3. If it ends with y with a consonant just before it, change the y to ies. ex. penny => pennies.

4. If it ends with f or fe, change it to ves. ex. knife => knives.

5. If it ends with o with a consonant just before it, change it to oes. ex.potato => potatoes.

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Task

You will be given a singular noun. You have to convert the given noun to plural and output it.

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Rules

• You will not be given irregular nouns, like mouse and moose.

• You will not be given exceptions, such as safe (safes; violating #4), piano (pianos; violating #5) and o (oes, violating #5).

• You will not be given words which have two or more possible plural forms, such as mosquito (mosquitos or mosquitoes) and roof (roofs or rooves).

• You will not be given uncountable nouns.

• y doesn't count as a vowel.

---

Examples

car => cars
bus => buses
potato => potatoes
knife => knives
penny => pennies
exception => exceptions
wolf => wolves
eye => eyes
decoy => decoys
radio => radios

Answer 1

Mathematica, 9 bytes

Pluralize

Yes, there is a built-in for this!

Sample output

Pluralize["car"]

cars

Pluralize /@ {"bus", "potato", "knife", "penny", "exception", "wolf", "eye"}

{"buses", "potatoes", "knives", "pennies", "exceptions", "wolves", "eyes"}

Answer 2

Retina, 57 53 56 55 58 57 bytes

Thanks to MartinEnder for some golfing suggestions

Thanks to BusinessCat for golfing 1 byte

([^aeiou]o|sh?|ch|z|x)$
$1e
fe?$
ve
([^aeiou])y$
$1ie
$
s

Try it online!

Explanation (outdated)

([^aeiou])y$
$1ie

Changes {consonant}y to {consonant}ie

([^aeiou]o|[fxzs]|[sc]h)$
$&e

Appends an e to when the word ends with an {consonant}o, f,x,z,s,sh or ch.

fe$
ve

Changes an ending fe to ve

$
s

Finally append an s to the word.

Edits

• Added bytes because I forgot the second rule
• Added bytes to update with eye as an example

Answer 3

JavaScript (ES6),  109  97 bytes

s=>s[R='replace'](/([^aeiou])y$/,'$1ie')[R](/fe?$/,'ve')[R](/([^aeiou]o|[sxz]|[cs]h)$/,'$1e')+'s'

Try it online!

Answer 4

Batch, 325 bytes

@set/ps=
@for %%v in (a e i o u)do @(
for %%e in (o y)do @if %s:~-2%==%%v%%e goto s
if %s:~-2%==%%vf set s=%s:~,-1%ve&goto s
if %s:~-3%==%%vfe set s=%s:~,-2%ve&goto s
)
@if %s:~-1%==y set s=%s:~,-1%ie
@for %%e in (o s x z)do @if %s:~-1%==%%e set s=%s%e
@for %%e in (c s)do @if %s:~-2%==%%eh set s=%s%e
:s
@echo %s%s

Answer 5

Haskell, 216 207 205 bytes

Thanks to @Lynn, @user1472751 and @Laikoni for the help!

import Data.List
(!)s=or.map(\x->x`isSuffixOf`s)
c=['b'..'z']\\"eiou"
p s|s!(words"s x z ch sh"++map(:"o")c)=s++"es"|s!map(:"y")c=init s++"ies"|s!["f"]=init s++"ves"|s!["fe"]=(init.init)s++"ves"|0<1=s++"s"

Readable

import Data.List;

endsWithOneOf :: String -> [String] -> Bool
endsWithOneOf str ends = (or . map (\end -> end `isSuffixOf` str)) ends 

consonants :: [Char]
consonants = ['a'..'z'] \\ "aeiou"

pluralize :: String -> String
pluralize str
    | str `endsWithOneOf` (words "s x z ch sh" ++ (map (:"o") consonants)) = str ++ "es"
    | str `endsWithOneOf` (map (:"y") consonants) = init str ++ "ies"
    | str `endsWithOneOf` ["f"] = init str ++ "ves"
    | str `endsWithOneOf` ["fe"] = (init.init) str ++ "ves"
    | otherwise = str ++ "s"

Explanation

import Data.List for the function isSuffixOf. endsWithOneOf (€ in the golfed version) returns whether one of the list elements is an ending of the string. consonants(c) is just a list of all consonants.

Finally, pluralize(p) checks for the endings and returns the proper pluralization.

Example:

p "potato" == "potatoes"

Answer 6

PHP, 103 100 bytes

<?=preg_replace(['/([^aeiou]o|sh?|x|z|ch)$/','/(?<![aeiou])y$/','/fe?$/'],['\1e',ie,ve],$argv[1]).s;

Try it online!

The preg_replace function takes in an array of patterns and replacements.

• Saved 2 bytes thanks to Titus.
• Saved 1 byte thanks to Dewi Morgan.

Answer 7

Röda, 80 bytes

f&s{s~="([^aeiou])y$","$1ie","([sxz]|[cs]h|[^aeiuo]o)$","$1e","fe?$","ve"s.="s"}

The function modifies its argument. Usage: main word { f word; print word } Here's a version that uses a return value (83 bytes):

f s{s~="([^aeiou])y$","$1ie","([sxz]|[cs]h|[^aeiuo]o)$","$1e","fe?$","ve";[s.."s"]}

And below is a function that reads infinitely many values from the input stream and pushes plural forms to the output stream (87 83 bytes):

{replace"([^aeiou])y$","$1ie","([sxz]|[cs]h|[^aeiuo]o)$","$1e","fe?$","ve","$","s"}

It's an anonymous function, as that is shorter than creating a named function.

Answer 8

Perl, 66 + 2 (-pl flag) = 68 bytes

$_.=/(ch|sh?|x|z|[^aeiou]o)$/+s/([^aeiou])y$/$1i/+s/fe?$/v/?es:"s"

Using:

perl -ple '$_.=/(ch|sh?|x|z|[^aeiou]o)$/+s/([^aeiou])y$/$1i/+s/fe?$/v/?es:"s"' <<< car

Try it on Ideone.

Answer 9

Python 3, 271 239 199 bytes

Thanks to @ovs for reducing it by 72 bytes!

lambda s,v="aeiou":(s[-2:]=="fe"and s[:-2]+"ve"or s[:-1]+((s[-1]=="y"and s[-2]not in v)*"ie"or s[-1]=="f"and"ve"or s[-1]+((s[-1]in"sxz"or s[-2:]in["ch","sh"])+(s[-1]=="o"and s[-2]not in v))*"e"))+"s"

Try it online!

Answer 10

sed, 70 79 bytes

69 78 + 1 for -E (BSD)/-r (GNU) flag

s/([^aeiou])y$/\1ie/
s/([^aeiou]o|[fxzs]|[sc]h)$/&e/
s/fe/ve/
s/$/s/

Direct port of the retina answer.

Answer 11

Pip, 63 61 bytes

Y`[^aeiou]`OaR[C`sh?|x|z|ch`Cy.'y`fe?`y.'o].'$[_B.'i'v_].'e's

So close to catching Retina! But it's probably not going to happen. :(

Try it online!

Explanation

Basic strategy: Replace performs several replacements one after the other when given lists of patterns and replacements. We want to make the following replacements:

• (sh?|x|z|ch)$ -> add an e
• [^aeiou]y -> change the y to i and add an e
• fe? -> change to v and add an e
• [^aeiou]o -> add an e

Then we want to tack on an s regardless.

Tricks:

• The C operator, given a regex, wraps it in a capturing group; C`xyz` is one byte shorter than `(xyz)`.
• A list of regexes or replacements that all end with the same character can be created by concatenating the character to the list instead of including it in all the items. Concatenating a Scalar (string) to a Pattern (regex/replacement) coerces to a Pattern.
• Instead of concatenating the s (and having to deal with the precedence ordering of R and .), we can simply Output the main part of the word and then print the s separately.

Spaced and commented code:

                  a is 1st cmdline input (implicit)
Y`[^aeiou]`       Yank the consonant regex into the y variable
O a R             Output (without newline): a, with the following replacements:
 [                List of regexes to replace:
  C `sh?|x|z|ch`    (sh?|x|z|ch)
  Cy . 'y           ([^aeiou])y
  `fe?`             fe?
  y . 'o            [^aeiou]o
 ] . '$           End of list; concatenate $ to each item
 [                List of replacements:
  _                 Identity function (replace with whole match)
  B                 B is short for {b}, a function returning its second argument; as a
                    callback function for regex replacement, the second argument is
                    the value of capturing group 1 (the consonant before y)
    . 'i            To that, concatenate i
  'v                Scalar literal v
  _                 Identity function
 ] . 'e           End of list; concatenate e to each item
's                Return Scalar literal s, which is autoprinted

Answer 12

C#, 73 163 bytes:

Func<string,string>p=System.Data.Entity.Design.PluralizationServices.PluralizationService.CreateService(System.Globalization.CultureInfo.CurrentCulture).Pluralize

Yes, another language with it built-in (although you need to add a reference to System.Data.Entity.Design.dll)

To use:

var words = new[] { "car", "bus", "potato", "knife", "penny", "exception", "wolf", "eye", "decoy", "radio" };
foreach (var word in words)
{
    var plural = p(word);
    Console.Out.WriteLine($"{word} => {plural}");
}

Output:

car => cars
bus => buses
potato => potatoes
knife => knives
penny => pennies
exception => exceptions
wolf => wolves
eye => eyes
decoy => decoys
radio => radios

Answer 13

Python 199 187 176 Bytes

lambda s:s+'\bve'*(s[-1]=='f')+'\b\bve'*(s[-2:]=='fe')+'e'*(s[-1]in'sxz'or s[-2:]in('ch','sh')or s[-1]=='o'and s[-2]not in'aiueo')+'\bie'*(s[-1]=='y'and s[-2]not in'aiueo')+'s'

Answer 14

Rails runner, 18 bytes

$><<gets.pluralize

Example:

$ echo knife | rails r filename.rb
knives

Answer 15

Python, 296 bytes

z = input()
if z[-1]in['s','x','z','ch','sh']:print(z+'es')
elif z[-1]=='y'and z[-2]not in['a','e','i','o','u']:print(z[:-1]+'ies')
elif z[-2:]=='fe':print(z[:-2]+'ves')
elif z[-1]=='f':print(z[:-1]+'ves')
elif z[-1]=='o'and z[-2]not in['a','e','i','o','u']:print(z[:-1]+'oes')
else:print(z+'s')

Answer 16

C, 321 bytes

#define E else if(
#define C unsigned char
C*p(C*b){static C r[999],i,w,n,m;for(n=w=i=0;r[i]=b[i];n=w,w=b[i++]);m=!strchr("aeiou",n);if(strchr("sxz",w)||(w=='h'&&strchr("cs",n))||(w=='o'&&m))r[i++]='e';E'y'==w&&m)r[i-1]='i',r[i++]='e';E'f'==w)r[i-1]='v',r[i++]='e';E'f'==n&&w=='e')r[i-2]='v';r[i++]='s';r[i]=0;return r;}

test:

C*mx[]={"car","bus","potato","knife","penny","exception","wolf","eye","decoy","radio",0};

main()
{unsigned i;
 for(i=0;mx[i];++i)
    printf("[%s] [%s]\n", mx[i], p(mx[i]));
 return 0;
}

results:

[car] [cars]
[bus] [buses]
[potato] [potatoes]
[knife] [knives]
[penny] [pennies]
[exception] [exceptions]
[wolf] [wolves]
[eye] [eyes]
[decoy] [decoys]
[radio] [radios]
[radio] [radios]

Answer 17

Direct port of Retina:

Ruby, 111 bytes

'sub(/([^aeiou])y/){"#{$1}ie"};sub(/(.*)([^aeiou]o|[fxzs]|[sc]h)$/){"#{$1}#{$2}e"};sub(/fe/,"ve");sub(/$/,"s")'

Try it online!

Invoke via ruby -lpe and supply a file as input.txt for first CLI argument.

Answer 18

Java 7, 408 bytes

Golfed:

boolean b="bcdfghjklmnpqrstvwxyzs".contains(String.valueOf(s.charAt(s.length()-2))); String x=s.substring(0,s.length()-1);if(s.endsWith("s")||s.endsWith("x")||s.endsWith("z")||s.endsWith("ch")||s.endsWith("sh"))return s+"es";if(s.endsWith("y")&&b)return x+"ies";if(s.endsWith("f")) return x+"ves";if(s.endsWith("fe"))return s.substring(0,s.length()-2)+"ves";if(s.endsWith("o")&&b)return s+"es";return s+="s";

Basically testing what the end of the String is and adding / replacing letters depending on what case it is. The boolean and String at the beginning are just for removing repetition in the test cases and making the code smaller.

Readable version:

public static String pluralize(String s){

// Consonant at the 2nd last position?
boolean b = "bcdfghjklmnpqrstvwxyzs".contains(String.valueOf(s.charAt(s.length()-2))); 

// Substring for cases where last letter needs to be replaced
String x = s.substring(0,s.length()-1);

if(s.endsWith("s") || s.endsWith("x") || s.endsWith("z") || s.endsWith("ch") || s.endsWith("sh"))
    return s + "es";
if(s.endsWith("y") && b)
    return x + "ies";
if(s.endsWith("f")) 
    return x + "ves";
if(s.endsWith("fe"))
    return s.substring(0,s.length()-2) + "ves";
if(s.endsWith("o") && b)
    return s + "es";

return s += "s";
}