Python: Dynamic nested for loops each with different range

Question

I want to create a code that can iterate over a dynamic number (N) of nested loops each with different range. For example:

N=3 
ranges=[[-3, -2, -1, 0, 1, 2, 3],
 [-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5],
  [-3, -2, -1, 0, 1, 2, 3]]

for x in ranges[0]:
    for y in ranges[1]:
        for z in range[2]:
            variable=[x, y, z]

Im new to python. As I went over similar questions posted here I have the understanding that this can be done with recursion or itertools. However, none of the answers posted solve this problem for a different range at each level. The closest posted question similar to mine was Variable number of nested for loops with fixed range . However, the answer posted by user633183 is coded in python 3.X and I am coding in python 2.7 so I couldn't implement it as some of its code does not work on python 2.7. Can you please help me to code this problem. Thanks!

You will get more and better answers if you create a [Minimal, Complete, and Verifiable](http://stackoverflow.com/help/mcve) example. Especially make sure that the input and expected test data are complete (not pseudo-data), and can be easily cut and and paste into an editor to allow testing proposed solutions. — Stephen Rauch, Jun 01 '18 at 05:05
Possible duplicate of [Iterating over a 2 dimensional python list](https://stackoverflow.com/questions/16548668/iterating-over-a-2-dimensional-python-list) — Anand Tripathi, Jun 01 '18 at 05:24

score 1 · Accepted Answer · answered Jun 01 '18 at 05:16

1

Your code is equivalent to itertools.product:

print(list(itertools.product(*ranges)))

answered Jun 01 '18 at 05:16

Austin

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Thanks. I used this code v=list(itertools.product(*ranges)) for i in range(len(v)): var=v[i] do Something with var – PJORR Jun 01 '18 at 05:32

score 1 · Answer 2 · answered Jun 01 '18 at 05:21

So, if I am understanding your question correctly, you want the values being iterated over to be [-3, -5, -3], [-2, -4, -2].... This can be accomplished easily with zip function built into python:

for x in zip(*ranges):
    # Do something with x

x will take on a tuple of all the first values, then a tuple of all the second values, etc, stopping when the shortest list ends. Using this * splat notation avoids even having to know about the number of lists being combined.

Python: Dynamic nested for loops each with different range

2 Answers2

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