stem accuracy

[Moustafa1Rizk1]

Dears,
i am trying to use stemmers for some of the words, however, the stemming is not accurate.

example

from nltk.stem import PorterStemmer
from nltk.stem.lancaster import LancasterStemmer

ps = PorterStemmer()
st = LancasterStemmer()

def prepareWord(word):
print(word, " : ", st.stem(word))
return st.stem(word)

input : shelves

result: shelv

expected shelf

i need to know what is the alternative or this is a defect

[Moustafa1Rizk1]

Dears.

 is there any update, alternative or workaround?

My Best Regards