arrayInde()

行列のインデックス要素の座標を返す

> x = matrix(c(2,1,3,5,4,6,11,10,12,8,7,9),3,4)
> x
    [,1] [,2] [,3] [,4]
[1,]    2    5   11    8
[2,]    1    4   10    7
[3,]    3    6   12    9

> x %>% arrayInd( c(3,4))
     [,1] [,2]
[1,]    2    1
[2,]    1    1
[3,]    3    1
[4,]    2    2
[5,]    1    2
[6,]    3    2
[7,]    2    4
[8,]    1    4
[9,]    3    4
[10,]    2    3
[11,]    1    3
[12,]    3    3