[R] generate combination multiset (set with repetition)
Reuben Cummings
reubano at gmail.com
Thu Dec 11 18:00:30 CET 2008
Hi,
This has been asked before but not sufficiently answered from what I
could find. How do you create combinations
with repetitions (multisets) in R?
If I have
> set <- array(1:3)
And I want to choose all combinations of picking 2 numbers, I want to
get a print out like
[,1] [,2]
[1,] 1 1
[2,] 1 2
[3,] 1 3
[4,] 2 2
[5,] 2 3
[6,] 3 3
subsets(set, 2, allow.repeat=T) should work, but I can't get the
multic package to install, t(combn(set,2)) was suggested but it
doesn't produce repetitions; expand.grid(rep(list(1:3), 2)) was also
suggested, but it produces permuations, not combinations.
Additionally, I would like to iterate through each resultant set for
large n (similar to the description for getNextSet {pcalg}). Any
suggestions?
Reuben Cummings
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