Python: Finding combinations

Question

I have a list, to make it easier to understand it's structure I'll write it out like so:

mylist = [[["a","b","c","d"]...]...]

Where the ... means the previous list is repeated (although the values inside may change)

An example list would be:

mylist = [[["a","b","c","d"], ["e","f","g","h"]], [["i", "j", "k", "l"]], [["m","n","o","p"], ["q","r","s","t"]]]

My current method is:

mylist2 = []
for a in mylist[0]:
    for b in mylist[1]:
        for c in mylist[2]:
            mylist2.append([a,b,c])

However this is very long, especially since in my actual code it goes on up to for x in mylist[35]

Is there a better way for me to write this code?

Answer 1

your code

%%timeit
mylist2 = []
for a in mylist[0]:
    for b in mylist[1]:
        for c in mylist[2]:
            mylist2.append([a,b,c])
# 809 ns ± 18.8 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

use itertools

import itertools
%%timeit
list(itertools.product(*mylist))
# 528 ns ± 11.4 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)