Explode a dict - get all combinations of values ​​in a dictionary

Question

I want to get all combinations of values ​​in a dictionary in the form of several dictionaries (each of which contains each key of the original, but only one value of the original values). Let's say I want to parameterize a function call with:

kwargs = {'a': [1, 2, 3], 'b': [1, 2, 3]}

How to get a list of all combinations like this:

combinations = [{'a': 1, 'b': 1}, {'a': 1, 'b': 2}, {'a': 1, 'b': 3},
                {'a': 2, 'b': 1}, {'a': 2, 'b': 2}, {'a': 2, 'b': 3},
                {'a': 3, 'b': 1}, {'a': 3, 'b': 2}, {'a': 3, 'b': 3}]

A kwargssevere number of keys may exist in the source , and each value is guaranteed to be iterable, but the number of values ​​is not fixed.

If possible: the final combinationsshould be a generator (not a list).

Answer 1

kwargs :

>>> kwargs = {'a': [1, 2, 3], 'b': [1, 2, 3]}
>>> flat = [[(k, v) for v in vs] for k, vs in kwargs.items()]
>>> flat
[[('b', 1), ('b', 2), ('b', 3)], [('a', 1), ('a', 2), ('a', 3)]]

itertools.product,

>>> from itertools import product
>>> [dict(items) for items in product(*flat)]
[{'a': 1, 'b': 1},
 {'a': 2, 'b': 1},
 {'a': 3, 'b': 1},
 {'a': 1, 'b': 2},
 {'a': 2, 'b': 2},
 {'a': 3, 'b': 2},
 {'a': 1, 'b': 3},
 {'a': 2, 'b': 3},
 {'a': 3, 'b': 3}]

itertools.product . , . map, .

>>> for item in map(dict, product(*flat)):
...     print(item)
...
...
{'b': 1, 'a': 1}
{'b': 1, 'a': 2}
{'b': 1, 'a': 3}
{'b': 2, 'a': 1}
{'b': 2, 'a': 2}
{'b': 2, 'a': 3}
{'b': 3, 'a': 1}
{'b': 3, 'a': 2}
{'b': 3, 'a': 3}

Answer 2

: , ( @thefourtheye : -).

>>> combinations = (dict(zip(kwargs, vs)) for vs in product(*kwargs.values()))
>>> for c in combinations:
        print(c)

{'a': 1, 'b': 1}
{'a': 1, 'b': 2}
{'a': 1, 'b': 3}
{'a': 2, 'b': 1}
{'a': 2, 'b': 2}
{'a': 2, 'b': 3}
{'a': 3, 'b': 1}
{'a': 3, 'b': 2}
{'a': 3, 'b': 3}