CODEWITHSUNDEEP
pythonarrayspython-3.xnumpy
harry
harry

Reputation: 53

Creating ND arrays at runtime with standard library

I have three arrays 

a = [2]
b = [2,3,6]
c = [1]

I want to merge them such that I get an array of size len(a)*len(b) containing all permutations of both. (C will always contain a single value)

I thought that something like this would work

newArr = [for i in range len(a)*len(b) [for x in a][for y in b][for z in c]]
print(newArr)

[[2,2,1],[2,3,1],[2,6,1]]

However it doesn't seem to allow it within the syntax of the language. Does anyone have any clue as to how I do this with standard libraries?

Upvotes: 3

Views: 49

Answers (2)

Joe Holloway
Joe Holloway

Reputation: 28948

Use itertools.product(...)

import itertools

a = [2]
b = [2,3,6]
c = [1]

p = itertools.product(a, b, c)

print(list(p))

[(2, 2, 1), (2, 3, 1), (2, 6, 1)]

Upvotes: 1

ForceBru
ForceBru

Reputation: 44888

[[x, y, z] for x in a for y in b for z in c]

For example:

>>> [[x, y, z] for x in [2] for y in [2,3,6] for z in [1]]
[[2, 2, 1], [2, 3, 1], [2, 6, 1]]

Upvotes: 2

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