How to make n-dimensional nested for-loops in Python? [duplicate]

Question

I have the following situation:

for x1 in range(x1, x2):
    for x2 in range(x3, x4):
        for x3 ...
            ...
                f(x1, x2, x3, ...)

How to convert this to a mechanism in which I only tell python to make n nested loops where the variable name is x1, x2, x3, x4, ...? I don't want to write every possibility manually of course, since there might be very many dimensions.

Answer 1

What you want to do is iterate over a product. Use itertools.product.

import itertools

ranges = [range(x1, x2), range(x3, x4), ...]

for xs in itertools.product(*ranges):
    f(*xs)

Example

import itertools

ranges = [range(0, 2), range(1, 3), range(2, 4)]

for xs in itertools.product(*ranges):
    print(*xs)

Output

0 1 2
0 1 3
0 2 2
0 2 3
1 1 2
1 1 3
1 2 2
1 2 3