Iterate over all possible combinations of list elements and use as indices in Python -

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i have following list:

indices = [125,144,192]

i want generate such structure want use combination of 3 of these numbers indices 3d list:

mylist[i][j][k] = somevar

where i,j, , k loop on of combinations shown below:

i,j,k = 0,0,0 i,j,k = 0,0,192 i,j,k = 0,144,0 i,j,k = 125,0,0 i,j,k = 0,144,192 i,j,k = 125,0,192 i,j,k = 125,144,0 i,j,k = 125,144,192

in other words, i'd simplify following:

for in [0,125]:     j in  [0,144]:         k in [0,192]:             mylist[i][j][k] = somevar

what pythonic way this?

you can use itertools.product :

>>> list(product([0,125],[0,144],[0,192])) [(0, 0, 0),   (0, 0, 192),   (0, 144, 0),   (0, 144, 192),   (125, 0, 0),   (125, 0, 192),   (125, 144, 0),   (125, 144, 192)]

or more general solution can use izip (in python 3 zip efficient ) , repeat create desire pairs , pass them product :

>>> indices = [125,144,192] >>> itertools import product,izip,repeat >>> list(product(*izip(repeat(0,len(indices)),indices))) [(0, 0, 0), (0, 0, 192), (0, 144, 0), (0, 144, 192), (125, 0, 0), (125, 0, 192), (125, 144, 0), (125, 144, 192)] >>>

and indexing can :

for i,j,k in product(*izip(repeat(0,len(indices)),indices)):     # stuff mylist[i][j][k]

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