from sklearn.feature_extraction.text import TfidfVectorizer

item = list(df['item1']) + list(df['item2'])
tfidf = TfidfVectorizer()
tfidf_sp = tfidf.fit_transform(item)

for i in len(list(df['item1'])):
    new_list =[]
    new_list.append(tfidf.idf_)
df['updated_item'] = list(new_list)

import pandas as pd

pd.DataFrame(tfidf_sp, columns = tfidf.get_feature_names())