Return a list in loop before loop start again

Question

My code:

lis2 = []
lis1 = []
for cm in comments:
    sp = cm.split()
    for s in sp:
        for tf in tfidf:
            if tf == s:
                lis2.append(tf)
            else:
                continue

lis1.append(lis2)      
print(lis1)            
data = pd.DataFrame(lis1)

In this code two lists:

1. comments: list of sentences
2. tfidf: a list of words.

I want to iterate every sentence (comments) and find any word from tfidf list and append it to a new list lis2.

Also, when first sentence is finished, append lis2 to lis1 then go to the next sentence.

But my code just return word like this:

[['custom', 'servic', 'portfolio', 'time', 'custom', 'servic', 'custom', 'servic', 'support', 'ticket', 'custom', 'servic', 'experi', 'platform', 'user', 'experi', 'account', 'portfolio', 'experi', 'user', 'experi', 'user', 'platform', 'account', 'time', 'fast', 'platform', 'custom', 'custom', 'account', 'time', 'fast', 'time', 'time', 'account', 'custom', 'servic', 'servic', 'account', 'user', 'custom', 'custom', 'account', 'time', 'account', 'user', 'time', 'account']

Answer 1

comments = ['a1 a2 a3',  'b1 b2 b3',  'c1 c2 c3']
tfidf = ['a2', 'b1', 'b3']

lis_1 = []

for sentence in comments:
    lis_2 = []
    words = sentence.split()
    for word in words:
        if word in tfidf:
            lis_2.append(word)
    # After all words of a sentence are processed:
    lis_1.append(lis_2)

print(lis_1)

Output:

[['a2'], ['b1', 'b3'], []]

---

You can get the same result more succinctly using a List Comprehension and sets:

lis_1 = [list(set(sentence.split()).intersection(tfidf)) for sentence in comments]