Python - get combination of data from array of arrays

Question

I have an array which holds other arrays which are holding possible values of data at given position. Example:

data = [['A'],['A','B'],['A','B'],['A','B','D'],['0','2']]

From this data possible values are (for example):

"AAAA0"  # (00000)  
"AAAA2"  # (00001)  
"AAAD0"  # (00020)

and so on.
What I would need, is to get all possible combinations of data from those single arrays, but order of data is important:

data from inner array can only be placed on its position in outer array (in above example on first position only 'A' can be placed)

Is there some Python module that will be able to handle this (I found itertools, but it's doing not exactly what I need), or maybe someone has some idea how to do this ?

This is not a code-writing service. Could you show us some code that you have tried so we can say what the problems are? You need to show more effort of your own. — Rory Daulton, Jul 31 '16 at 22:45
I've tried this: `import itertools print (list(itertools.combinations([['A'],['B','C'],['D','E','F']], 2)))` with result: [(['A'], ['B', 'C']), (['A'], ['D', 'E', 'F']), (['B', 'C'], ['D', 'E', 'F'])] — name, Jul 31 '16 at 22:46
Possible duplicate of [Get the cartesian product of a series of lists in Python](http://stackoverflow.com/questions/533905/get-the-cartesian-product-of-a-series-of-lists-in-python) — donkopotamus, Jul 31 '16 at 22:58

score 1 · Accepted Answer · answered Jul 31 '16 at 22:51

1

I think you need the itertools.product here:

import itertools
[''.join(p) for p in itertools.product(*data)]

#['AAAA0',
# 'AAAA2',
# 'AAAB0',
# 'AAAB2',
# 'AAAD0',
# 'AAAD2',
# 'AABA0',
# 'AABA2',
# 'AABB0',
# 'AABB2',
# 'AABD0',
# 'AABD2',
# 'ABAA0',
# 'ABAA2',
# 'ABAB0',
# 'ABAB2',
# 'ABAD0',
# 'ABAD2',
# 'ABBA0',
# 'ABBA2',
# 'ABBB0',
# 'ABBB2',
# 'ABBD0',
# 'ABBD2']

answered Jul 31 '16 at 22:51

Psidom

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That seems to do exactly what I needed. Thank for fast help to all who responded. Also answer of David Gomes was helpful, but this one-liner does the job. – name Jul 31 '16 at 23:20

score 0 · Answer 2 · answered Jul 31 '16 at 22:50

Try this:

data = [['A'], ['A','B'], ['A','B'], ['A','B','D'], ['0','2']]
size = 5

def rec(cur):
    if len(cur) == size:
        print(cur)
        return

    for x in data[len(cur)]:
        rec(cur + [x])

rec([])

Output:

['A', 'A', 'A', 'A', '0']
['A', 'A', 'A', 'A', '2']
['A', 'A', 'A', 'B', '0']
['A', 'A', 'A', 'B', '2']
['A', 'A', 'A', 'D', '0']
['A', 'A', 'A', 'D', '2']
['A', 'A', 'B', 'A', '0']
['A', 'A', 'B', 'A', '2']
['A', 'A', 'B', 'B', '0']
['A', 'A', 'B', 'B', '2']
['A', 'A', 'B', 'D', '0']
['A', 'A', 'B', 'D', '2']
['A', 'B', 'A', 'A', '0']
['A', 'B', 'A', 'A', '2']
['A', 'B', 'A', 'B', '0']
['A', 'B', 'A', 'B', '2']
['A', 'B', 'A', 'D', '0']
['A', 'B', 'A', 'D', '2']
['A', 'B', 'B', 'A', '0']
['A', 'B', 'B', 'A', '2']
['A', 'B', 'B', 'B', '0']
['A', 'B', 'B', 'B', '2']
['A', 'B', 'B', 'D', '0']
['A', 'B', 'B', 'D', '2']

Python - get combination of data from array of arrays

2 Answers2