How can I create list comprehension with multiple dictionary items?

Question

I am trying to create multiple lists from a dictionary. For example:

dict_ = {'one': 1, 'two': 2, 'three': 3, 'four': 4}
list_1 = [k for k, v in dict_.items()]
list_2 = [v for k, v in dict_.items()]

The above works but I am trying to find out if there is a single liner that would create both list_1 and list_2 instead of repeating the same "for" loop twice?

You can do `list_1 = list(dict_.keys())`, `list_2 = list(dict_.values())`. Alternatively `list_1 = list(dict_)` — alani, Oct 07 '20 at 19:35
If you really want a one-liner, you can of course use `list_1, list_2 = .... , ....` but I'm not sure whether that improves the code. — alani, Oct 07 '20 at 19:37
If you want to use the same loop (which is good), why you feel like you need it to be in one line? What's wrong with a regular `for` loop? — Tomerikoo, Oct 07 '20 at 19:37

Chris Greening · Accepted Answer · 2020-10-07T19:53:59.377

3

You could try something with multiple assignment if you really wanted to:

list_1, list_2 = list(dict_.keys()), list(dict_.values())

or you could use a single listcomp

list_1, list_2 = [list(tup) for tup in zip(*dict_.items())]

or if you're feeling functional you could try

list_1, list_2 = map(list, zip(*dict_.items()))

but readability counts and simple is better than complex so the two separate lines are probably a better approach

edited Oct 07 '20 at 19:53

answered Oct 07 '20 at 19:38

Chris Greening

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In all honesty I'd write it in two separate lines (as I mentioned in comments below the question), but I guess the OP wants a one-liner... – alani Oct 07 '20 at 19:40
Thanks for the edit... – alani Oct 07 '20 at 19:43
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I'm giving OP what they asked but I would personally keep it as two separate lines as well lol – Chris Greening Oct 07 '20 at 19:44
Thank you! Really appreciate your help – Tom Cider Oct 07 '20 at 20:03

score 2 · Answer 2 · answered Oct 07 '20 at 19:38

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dict_ = {'one': 1, 'two': 2, 'three': 3, 'four': 4}
list_1, list_2 = list(dict_.keys()), list(dict_.values())

answered Oct 07 '20 at 19:38

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How can I create list comprehension with multiple dictionary items?

2 Answers2