Enumerating three variables in python list comprehension

Question

I am trying to print all the possible enumerations of a list for three variables. For example if my input is:

x = 1
y = 1
z = 1

I want the output to be like:

[[0, 0, 0], [0, 0, 1], [0, 1, 0], [1, 0, 0], [1, 1, 0], [1, 0, 1], [0, 1, 1], [1, 1, 1]]

If any of the x,y,z variables are higher than 1, it would enumerate all the integers from 0 to the variable value. For example, if x=3 then 0, 1, 2, or 3 would be possible in the first slot of the 3-element lists.

Right now I am creating the list comprehension like this:

output = [ [x,y,z] for x,y,z in range(x,y,z)]

I think something is wrong with the range function?

Answer 1

Complementary to the solutions using product, you could also use a triple list comprehension.

>>> x, y, z = 1, 2, 3
>>> [(a, b, c) for a in range(x+1) for b in range(y+1) for c in range(z+1)]
[(0, 0, 0),
 (0, 0, 1),
 (0, 0, 2),
 (some more),
 (1, 2, 2),
 (1, 2, 3)]

The +1 is necessary since range does not include the upper bound. If you want the output to be a list of lists, you can just do [[a, b, c] for ...].

Note, however, that this will obviously only work is you always have three variables (x, y, z), while product would work with an arbitrary number of lists/upper limits.

Answer 2

You could use the product() function from itertools as follows:

from itertools import product

answer = list(list(x) for x in product([0, 1], repeat=3))
print(answer)

Output

[[0, 0, 0], [0, 0, 1], [0, 1, 0], [0, 1, 1], [1, 0, 0], [1, 0, 1], [1, 1, 0], [1, 1, 1]]