# MATLAB: Find a subset of unique permutations

permsunique

I have many arrays A of varying length. For any given A, I'd like to find all the unique sets of three elements of A. For example, if A has five elements:
A = [5 6 2 4 7];
one combination of three elements in A is [5 6 2], another combination is [5 6 4], and so on. When I work this out manually I get these combinations:
5 6 2   5 6   4   5 6     75   2 4  5   2   75     4 7  6 2 4    6 2   7  6   4 7    2 4 7
The appearance of the solutions above makes me think there may be a clever way to use an identity matrix, but I can't quite think of how. Or perhaps there's a way to use perms, perhaps with sort and unique?
Can you think of a way to get all 3-element subsets of an array?

Why not use NCHOOSEK?
A = [5 6 2 4 7]; nchoosek(A,3)ans =       5     6     2       5     6     4       5     6     7       5     2     4       5     2     7       5     4     7       6     2     4       6     2     7       6     4     7       2     4     7