I'm trying to find an elegant way to generate all possible combinations from an initial flat list.
For example:
[In:]
l = ["aaa", "bbb", "ccc"]
[Out:]
[["aaa"], ["bbb"], ["ccc"]]
[["aaa", "bbb"], ["ccc"]]
[["aaa", "ccc"], ["bbb"]]
[["bbb", "ccc"], ["aaa"]]
[["aaa", "bbb", "ccc"]]
As you see here the order doesn't matter for me. So I would avoid to obtain such cases:
[["aaa"], ["bbb"], ["ccc"]]
[["bbb"], ["aaa"], ["ccc"]]
...
[["ccc"], ["aaa"], ["bbb"]]
Also each sublist of my output list has to contain every element of my initial list.
I din't find any obvious solution with itertools.combination()
Thanks
Question is quite vague, I think what you are looking for is set-partitions:
def partition(collection):
if len(collection) == 1:
yield [ collection ]
return
first = collection[0]
for smaller in partition(collection[1:]):
# insert `first` in each of the subpartition's subsets
for n, subset in enumerate(smaller):
yield smaller[:n] + [[ first ] + subset] + smaller[n+1:]
# put `first` in its own subset
yield [ [ first ] ] + smaller
something = ['a', 'b', 'c']
for n, p in enumerate(partition(something), 1):
print(n, sorted(p))
Output:
1 [['a', 'b', 'c']]
2 [['a'], ['b', 'c']]
3 [['a', 'b'], ['c']]
4 [['a', 'c'], ['b']]
5 [['a'], ['b'], ['c']]
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.