tf-idf with lemmatizer about pke HOT 1 CLOSED

import pke

text = '''pke is an open source python-based keyphrase extraction toolkit.'''

extractor = pke.unsupervised.TopicRank()

extractor.load_document(input=text, language='en', normalization=None)
print(extractor.sentences[0].stems)
> ['pke', 'is', 'an', 'open', 'source', 'python', '-', 'based', 'keyphrase', 'extraction', 'toolkit', '.']

extractor.load_document(input=text, language='en', normalization='stemming')
print(extractor.sentences[0].stems)
> ['pke', 'is', 'an', 'open', 'sourc', 'python', '-', 'base', 'keyphras', 'extract', 'toolkit', '.']

extractor.load_document(input=text, language='en', normalization='lemmatization')
print(extractor.sentences[0].stems)
> ['pke', 'be', 'an', 'open', 'source', 'python', '-', 'base', 'keyphrase', 'extraction', 'toolkit', '.']