# Generate unique permutations of set and subsets

I’d like to generate permutations of an iterable, including those for subsets of the iterable, without duplicates or the empty set:

```(1,2,3)  -->  (
(1,),
(2,),
(3,),
(1, 2),
(1, 3),
(2, 3),
(1, 2, 3),
(1, 3, 2),
(2, 1, 3),
(2, 3, 1),
(3, 1, 2),
(3, 2, 1)
)
```

This is essentially the `powerset` function provided by `more-itertools` combined with `itertools.permutations`:

```from itertools import combinations, permutations

def powerset_permutations(iterable):
"([1,2]) --> (1,) (2,) (1,2) (2,1)"
s = list(iterable)
for r in range(1, len(s)):
yield from combinations(s, r)
yield from permutations(s)
```
```>>> list(powerset_permutations([1, 2, 3]))
[(1,), (2,), (3,), (1, 2), (1, 3), (2, 3), (1, 2, 3), (1, 3, 2), (2, 1, 3), (2, 3, 1), (3, 1, 2), (3, 2, 1)]
```

To include the empty set, change `range(1, len(s))` to `range(len(s))`:

```def powerset_permutations(iterable):
"([1,2]) --> (1,) (2,) (1,2) (2,1)"
s = list(iterable)
for r in range(len(s)):
yield from combinations(s, r)
yield from permutations(s)
```
```>>> list(powerset_permutations([1,2,3]))
[(), (1,), (2,), (3,), (1, 2), (1, 3), (2, 3), (1, 2, 3), (1, 3, 2), (2, 1, 3), (2, 3, 1), (3, 1, 2), (3, 2, 1)]
```