# Natural Language Toolkit: Stemmers # # Copyright (C) 2001-2018 NLTK Project # Author: Trevor Cohn # Edward Loper # Steven Bird # URL: # For license information, see LICENSE.TXT """ NLTK Stemmers Interfaces used to remove morphological affixes from words, leaving only the word stem. Stemming algorithms aim to remove those affixes required for eg. grammatical role, tense, derivational morphology leaving only the stem of the word. This is a difficult problem due to irregular words (eg. common verbs in English), complicated morphological rules, and part-of-speech and sense ambiguities (eg. ``ceil-`` is not the stem of ``ceiling``). StemmerI defines a standard interface for stemmers. """ from nltk.stem.api import StemmerI from nltk.stem.regexp import RegexpStemmer from nltk.stem.lancaster import LancasterStemmer from nltk.stem.isri import ISRIStemmer from nltk.stem.porter import PorterStemmer from nltk.stem.snowball import SnowballStemmer from nltk.stem.wordnet import WordNetLemmatizer from nltk.stem.rslp import RSLPStemmer