Unpacking a list / tuple of pairs into two lists / tuples

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Chapters
00:00 Question
00:40 Accepted answer (Score 493)
01:14 Answer 2 (Score 36)
01:24 Thank you

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Full question
https://stackoverflow.com/questions/7558...

Question links:
[A Transpose/Unzip Function in Python]: https://stackoverflow.com/questions/1933...

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Content licensed under CC BY-SA
https://meta.stackexchange.com/help/lice...

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Tags
#python #list #tuples

#avk47

ACCEPTED ANSWER

Score 552

>>> source_list = [('1','a'),('2','b'),('3','c'),('4','d')]
>>> list1, list2 = zip(*source_list)
>>> list1
('1', '2', '3', '4')
>>> list2
('a', 'b', 'c', 'd')

Edit: Note that zip(*iterable) is its own inverse:

>>> list(source_list) == zip(*zip(*source_list))
True

When unpacking into two lists, this becomes:

>>> list1, list2 = zip(*source_list)
>>> list(source_list) == zip(list1, list2)
True

Addition suggested by rocksportrocker.

ANSWER 2

Score 41

list1 = (x[0] for x in source_list)
list2 = (x[1] for x in source_list)