Lemmatization of all pandas cells

You can use apply from pandas with a function to lemmatize each words in the given string. Note that there are many ways to tokenize your text. You might have to remove symbols like . if you use whitespace tokenizer.

Below, I give an example on how to lemmatize a column of example dataframe.

import nltk

w_tokenizer = nltk.tokenize.WhitespaceTokenizer()
lemmatizer = nltk.stem.WordNetLemmatizer()

def lemmatize_text(text):
    return [lemmatizer.lemmatize(w) for w in w_tokenizer.tokenize(text)]

df = pd.DataFrame(['this was cheesy', 'she likes these books', 'wow this is great'], columns=['text'])
df['text_lemmatized'] = df.text.apply(lemmatize_text)

|col| 
['Sushi Bars', 'Restaurants']
['Burgers', 'Fast Food', 'Restaurants']

wnl = WordNetLemmatizer()

The below creates a function which takes list of words and returns list of lemmatized words. This should work.

def lemmatize(s):
'''For lemmatizing the word
'''
     s = [wnl.lemmatize(word) for word in s]
     return s

dataset = dataset.assign(col_lemma = dataset.col.apply(lambda x: lemmatize(x))