How to make a jagged array neat in Python?

Question

I have an array like this: ['a', ['e', 'r', 't'], 'c'].

I want to use some sort of processing to make the array neat: [['a', 'e', 'c'], ['a', 'r', 'c'], ['a', 't', 'c']].

If the array is: ['a', ['e', 'r', 't'], ['c', 'd']].

The result is: [['a', 'e', 'c'], ['a', 'e', 'd'], ['a', 'r', 'c'], ['a', 'r', 'd'], ['a', 't', 'c'], ['a', 't', 'd']].

And the length of the array is not fixed to 3, other examples:

['a', 'b'] = > ['a', 'b']
['a', ['b', 'c']] => [['a', 'b'], ['a', 'c']]
['ab', ['b', 'c']] => [['ab', 'b'], ['ab', 'c']]
[[1, 2], 3, 4] => [[1, 3, 4], [2, 3, 4]]

So what should I do? Is there a solution in Numpy?

What's the expected output for - ['a', ['e', 'r', 't'], ['b', 'c']]? — Divakar
– Divakar, Commented Jul 6, 2018 at 7:09
Is the depth consistent ? What about ['a', ['e', 'r', ['t', 'y']], 'c'] — BcK
– BcK, Commented Jul 6, 2018 at 7:14
did you mean that you want to convert some elements to a list and add to them things later? — dsal3389
– dsal3389, Commented Jul 6, 2018 at 7:18
Thanks, I modified my question, the highest depth is 2.@Divakar @Bck — Martin Zhu
– Martin Zhu, Commented Jul 6, 2018 at 7:24

tobias_k · Accepted Answer · 2018-07-06 10:01:57Z

3

Unless I misunderstand the question, you just want the product of the sub-lists, although you have to wrap any single elements into lists first.

>>> from itertools import product
>>> arr = ['a', ['e', 'r', 't'], ['c', 'd']]
>>> listified = [x if isinstance(x, list) else [x] for x in arr]
>>> listified
[['a'], ['e', 'r', 't'], ['c', 'd']]
>>> list(product(*listified))
[('a', 'e', 'c'),
 ('a', 'e', 'd'),
 ('a', 'r', 'c'),
 ('a', 'r', 'd'),
 ('a', 't', 'c'),
 ('a', 't', 'd')]

edited Jul 6, 2018 at 10:01

answered Jul 6, 2018 at 9:56

tobias_k

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1 Comment

YaOzI Over a year ago

Yes, I think this is neat way to do it.

Martin Zhu · Accepted Answer · 2018-07-06 09:49:11Z

0

I have a recursive solution:

inlist1 = ['ab', ['e', 'r', 't'], ['c', 'd']]
inlist2 = [['a', 'b'], ['e', 'r', 't'], ['c', 'd']]
inlist3 = [['a', 'b'], 'e', ['c', 'd']]


def jagged(inlist):
    a = [None] * len(inlist)

    def _jagged(index):
        if index == 0:
            print(a)
            return
        v = inlist[index - 1]
        if isinstance(v, list):
            for i in v:
                a[index - 1] = i
                _jagged(index - 1, )
        else:
            a[index - 1] = v
            _jagged(index - 1)

    _jagged(len(inlist))


jagged(inlist3)

answered Jul 6, 2018 at 9:49

Martin Zhu

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