Python's regex module re allows you to establish english plural rules in a more condensed from. This one should take care of most common plurals, you may add more rules ...
# using module re to pluralize most common english words
# (rule_tuple used as function default, so establish it first)
import re
# (pattern, search, replace) regex english plural rules tuple
rule_tuple = (
('[ml]ouse$', '([ml])ouse$', '\\1ice'),
('child$', 'child$', 'children'),
('booth$', 'booth$', 'booths'),
('foot$', 'foot$', 'feet'),
('ooth$', 'ooth$', 'eeth'),
('l[eo]af$', 'l([eo])af$', 'l\\1aves'),
('sis$', 'sis$', 'ses'),
('man$', 'man$', 'men'),
('ife$', 'ife$', 'ives'),
('eau$', 'eau$', 'eaux'),
('lf$', 'lf$', 'lves'),
('[sxz]$', '$', 'es'),
('[^aeioudgkprt]h$', '$', 'es'),
('(qu|[^aeiou])y$', 'y$', 'ies'),
('$', '$', 's')
)
def regex_rules(rules=rule_tuple):
for line in rules:
pattern, search, replace = line
yield lambda word: re.search(pattern, word) and re.sub(search, replace, word)
def plural(noun):
for rule in regex_rules():
result = rule(noun)
if result:
return result
# testing ...
print plural("man") # men
print plural("woman") # women
print plural("lady") # ladies
print plural("wife") # wives
print plural("leaf") # leaves
# okay according to Webster ...
print plural("index") # indexes
print plural("fungus") # funguses
# etc.
