行列でランダムシャッフル
applyの引数2つ目が「1」か「2」かで行(=1)か列(=2)かが決まる.
> tmp <- matrix(1:10,ncol=2,nrow=5) > tmp [,1] [,2] [1,] 1 6 [2,] 2 7 [3,] 3 8 [4,] 4 9 [5,] 5 10 > apply(tmp,1,sample) #行方向のシャッフル [,1] [,2] [,3] [,4] [,5] [1,] 1 2 8 9 5 [2,] 6 7 3 4 10 > apply(tmp,2,sample) #列方向のシャッフル [,1] [,2] [1,] 5 9 [2,] 3 10 [3,] 4 8 [4,] 2 6 [5,] 1 7