3 replies to this topic

[Turboorav]

I have a list of numbers and I want to check all the combinations. How can I do it?
Let's say I have a list that contains:
1,2,3,4

Then I want to check all the combinations that are unique:
1
1,2
1,2,3
1,2,4
1,2,3,4
1,3
1,3,4
1,4

2
2,3
2,3,4
2,4

3
3,4

4

[WingedPanther]

One way would be to count, using the bits to indicate which numbers to include:
0001
0010
0011
0100
0101
...

[JackomoLight]

Well haven't you studied about factorials? All possible(unique) combinations of a set of different(non-repetitive) n elements is given by n! ( n factorial) I bet there is a function in the math library for doing that but I never used it you can simply write 3 lines recursive function and you are done.

[solartic]

python's itertools has permutations and combinations funtions

from itertools import combinations

>>> for x in range(1,5): print list(combinations([1,2,3,4], x))
...
[(1,), (2,), (3,), (4,)]
[(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]
[(1, 2, 3), (1, 2, 4), (1, 3, 4), (2, 3, 4)]
[(1, 2, 3, 4)]