All combinations of all sizes?
combinations, r
Solution
If you prefer compact code
Map(combn, list(x), seq_along(x))
## [[1]]
## [,1] [,2] [,3] [,4]
## [1,] 1 2 3 4
## [[2]]
## [,1] [,2] [,3] [,4] [,5] [,6]
## [1,] 1 1 1 2 2 3
## [2,] 2 3 4 3 4 4
## [[3]]
## [,1] [,2] [,3] [,4]
## [1,] 1 1 1 2
## [2,] 2 2 3 3
## [3,] 3 4 4 4
## [[4]]
## [,1]
## [1,] 1
## [2,] 2
## [3,] 3
## [4,] 4
To avoid repetition, you'll have to deal with nested list but you can simplify the result using `unlist`
res <- Map(combn, list(x), seq_along(x), simplify = FALSE)
unlist(res, recursive = FALSE)
## [[1]]
## [1] 1
## [[2]]
## [1] 2
## [[3]]
## [1] 3
## [[4]]
## [1] 4
## [[5]]
## [1] 1 2
## [[6]]
## [1] 1 3
## [[7]]
## [1] 1 4
## [[8]]
## [1] 2 3
## [[9]]
## [1] 2 4
## [[10]]
## [1] 3 4
## [[11]]
## [1] 1 2 3
## [[12]]
## [1] 1 2 4
## [[13]]
## [1] 1 3 4
## [[14]]
## [1] 2 3 4
## [[15]]
## [1] 1 2 3 4
Problem
There are thousands of results on SO when I search for "vector combinations in R" but I can't find the answer to my question. Apologies if it is a duplicate: I have a vector `(1,2,3,4)` and I want to find all combinations (n choose 2) to (n choose n). In other words, for this vector I would want: ``` 1,2,3,4 1,2,3 1,2,4 1,3,4 2,3,4 1,2 1,3 1,4 2,3 2,4 3,4 ``` And hopefully the code would be generalizable so that once I have a larger vector, it would be able to generalize. Thanks!