CODEWITHSUNDEEP
rfunctioncombinationspermutation
Btzzzz
Btzzzz

Reputation: 143

Function for permutation of different size vectors in R

I want to create a which creates all possible s of distinct vectors with elements -1,0,1 for different size vectors.

e.g. for vectors of size 2 then i'd have 3^2 vectors. This is easy to write down as below, but if i want to do it for vectors of size 6, i'd have to write 729. 

x1 = c(1,1)
x2= c(1,0)
x3 = c(1,-1)
x4 = c(0,0)
x5 = c(0,1)
x6 = c(0,-1)
x7= c(-1,1)
x8 = c(-1,0)
x9 = c(-1,-1)

For size 3 vectors...

(1,1,1)
(1,1,0)
(1,1,-1)
(1,0,0)..... etc

Any ideas how can I make this more simplified? Thanks.

Upvotes: 1

Views: 50

Answers (1)

Ian Campbell
Ian Campbell

Reputation: 24838

Here's one approach with expand.grid.

expand.grid(c(-1:1),c(-1:1),c(-1:1))

Or for arbitrary length vectors. 

expand.grid(rep(list(c(-1:1)),4))
   Var1 Var2 Var3 Var4
1    -1   -1   -1   -1
2     0   -1   -1   -1
3     1   -1   -1   -1
4    -1    0   -1   -1
5     0    0   -1   -1
6     1    0   -1   -1
7    -1    1   -1   -1
8     0    1   -1   -1
9     1    1   -1   -1
10   -1   -1    0   -1

Upvotes: 3

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