Python: How to split a list based on a specific element

Question

If we have the following list in Python

sentence = ["I", "am", "good", ".", "I", "like", "you", ".", "we", "are", "not", "friends", "."]

How do I split this to get a list which contains elements that finish with the full stop? So i want to get the following elements in my new list:

["I","am","good","."]
["I","like","you","."]
["we","are","not","friends","."]

My attempts so far:

cleaned_sentence = []
a = 0
while a < len(sentence):
    current_word = sentence[a]
    if current_word == "." and len(cleaned_sentence) == 0:
        cleaned_sentence.append(sentence[0:sentence.index(".")+1])
        a += 1
    elif current_word == "." and len(cleaned_sentence) > 0:
        sub_list = sentence[sentence.index(".")+1:-1]
        sub_list.append(sentence[-1])
        cleaned_sentence.append(sub_list[0:sentence.index(".")+1])
        a += 1
    else:
        a += 1

for each in cleaned_sentence:
    print(each)

Running this on sentence produces

['I', 'am', 'good', '.']
['I', 'like', 'you', '.']
['I', 'like', 'you', '.']

Answer 1

You can use itertools.groupby:

from itertools import groupby
i = (list(g) for _, g in groupby(sentence, key='.'.__ne__))
print([a + b for a, b in zip(i, i)])

This outputs:

[['I', 'am', 'good', '.'], ['I', 'like', 'you', '.'], ['we', 'are', 'not', 'friends', '.']]

If your list doesn't always end with '.' then you can use itertools.zip_longest instead:

sentence = ["I", "am", "good", ".", "I", "like", "you", ".", "we", "are", "not", "friends"]
i = (list(g) for _, g in groupby(sentence, key='.'.__ne__))
print([a + b for a, b in zip_longest(i, i, fillvalue=[])])

This outputs:

[['I', 'am', 'good', '.'], ['I', 'like', 'you', '.'], ['we', 'are', 'not', 'friends']]