Python reorder lists inside lists

Question

Hopefully I can explain this well I have a list that is n in length but for this example lets use this.

List = [[['a','b','c'], [1,2,3], [7,8,9]],[['e','f','g'], [4,5,6], [1,2,3]]]

I want to change up all the values to yield

List = [[['a',1,7], ['b',2,8], ['c',3,9]], [['f',4,1], ['g',5,2], ['c',6,3]]]

so essentially List[0][0], List[1][0], List[2][0] and so on. I have tried a bunch of stuff and I cant quite find the write mix to get this working. any help would be appreciated

I have attempted too many things to count and non of them are particularly valuable so ill leave that out for now.

What happened to "f" and "g"? Or is this a typo/copy-paste-error? — tobias_k, Jan 27 '16 at 21:29
You can use numpy: `import numpy as np; print([b.T for b in np.array([[['a','b','c'], [1,2,3], [7,8,9]],[['e','f','g'], [4,5,6], [1,2,3]]])])` — Nicolas Heimann, Jan 27 '16 at 21:35

Jared Goguen · Accepted Answer · 2016-01-27T21:46:58.260

2

Use zip!

[[list(x) for x in zip(*sublist)] for sublist in List ]

Or, with unequal lengths:

[map(None, *sublist) for sublist in List] # Python 2
[list(itertools.zip_longest(*sublist)) for sublist in List] # Python 3

If you can be ensured that the sublists are of equal length and tuples would suffice instead of lists, then:

[zip(*sublist) for sublist in List]

edited Jan 27 '16 at 21:46

answered Jan 27 '16 at 21:29

Jared Goguen

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that works on python 2 only, me thinks – Pynchia Jan 27 '16 at 21:38
not enough. `zip` does not produce a list, but a tuple. – Pynchia Jan 27 '16 at 21:41
edited per above comments – Jared Goguen Jan 27 '16 at 21:43
OK, but do you check your code? The first line produces `[['a', 1, 7], ['b', 2, 8], ['c', 3, 9], ['e', 4, 1], ['f', 5, 2], ['g', 6, 3]]` on python 3 – Pynchia Jan 27 '16 at 21:45
part of me knew it didn't make sense to add another `for` statement without another comprehension – Jared Goguen Jan 27 '16 at 21:47
it's alright now, thank you. I had come up with `[list(map(list,zip(*el))) for el in List]`. :) – Pynchia Jan 27 '16 at 21:49
ooo, you can even get rid of the first `list` to have: `[map(list,zip(*sublist)) for sublist in List]` – Jared Goguen Jan 27 '16 at 21:51
not on python 3. That was my whole point. No indication was given about the python version used by the OP, so it's always better to cover both (with distinct solutions as in this case or with one that works on 2 and 3) – Pynchia Jan 27 '16 at 21:52
thanks for the help! o_o's comment knocked it out like a young veral mike tyson! [map(list,zip(*sublist)) for sublist in List] and this is all in Python 2.7, should have mentioned that. – dave_does_not_understand Jan 27 '16 at 21:58

Python reorder lists inside lists

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