Just make it so that it appends “s” unless the word ends with “y” or some other exception:
def plural(word):
wordlist = []
for char in word:
wordlist.append(char)
if word[len(word)-1] == "y":
wordlist[len(word)-1] = "ies"
else:
wordlist.append("s")
word = ""
for i in wordlist:
word+=i
return word
print(plural("STRING"))
solved Need a Python program Singular to Plural [closed]