Get all permutations of a numpy array

if your permutations fit in the memory, you could store them in a set and thus only get the distinguishable permutations.

from itertools import permutations

a = [0, 1, 0, 2]

perms = set(permutations(a))

Your a is what combinatorists call a multiset. The sympy library has various routines for working with them.

>>> from sympy.utilities.iterables import multiset_permutations
>>> import numpy as np
>>> a = np.array([0, 1, 0, 2])
>>> for p in multiset_permutations(a):
...     p
...     
[0, 0, 1, 2]
[0, 0, 2, 1]
[0, 1, 0, 2]
[0, 1, 2, 0]
[0, 2, 0, 1]
[0, 2, 1, 0]
[1, 0, 0, 2]
[1, 0, 2, 0]
[1, 2, 0, 0]
[2, 0, 0, 1]
[2, 0, 1, 0]
[2, 1, 0, 0]