How can I get all combinations of a list?

Question

I am trying to get all combinations of a list. Here is an example:

>>> l = [1, 2, 3]
>>> combo = something
>>> print(combo)
[1, 2, 3, 12, 13, 21, 23, 31, 32, 123, 132, 213, 231, 312, 321]

Here is what I tried so far:

>>> import itertools
>>> numbers = [1, 2, 3]
>>> l = list(itertools.permutations(numbers))
>>> print(l)
[(1, 2, 3), (1, 3, 2), (2, 1, 3), (2, 3, 1), (3, 1, 2), (3, 2, 1)]

How do I get the output [1, 2, 3, 12, 13, 21, 23, 31, 32, 123, 132, 213, 231, 312, 321] ?

Answer 1

Working code:

import itertools

numbers = [1, 2, 3]
result = []
for n in range(1, len(numbers) + 1):
    for x in itertools.permutations(numbers, n):  # n - length of each permutation
        result.append(int(''.join(map(str, x))))
print(result)

Output:

[1, 2, 3, 12, 13, 21, 23, 31, 32, 123, 132, 213, 231, 312, 321]

Answer 2

I believe the function you are looking at is:

 itertools.combinations(iterable, r)

It does the combination of the array iterable in r elements.

So:

>>> import itertools
>>> numbers = [1,2,3]
>>> l = list(itertools.combinations(numbers,2)) # combinations of two
>>> print(l)
[(1, 2), (1, 3), (2, 3)]

You can have more details at the documentation .