Dear all,
I found a difference between the indexing of an array and that of a matrix when there
are NA's in the index array. The screen copy is as follows.
> A <- array(NA, dim=6)
> A
[1] NA NA NA NA NA NA
> idx <- c(1,NA,NA,4,5,6)
> B <- c(10,20,30,40,50,60)
> A[idx] <- B
> A
[1] 10 NA NA 40 50 60
> AA <- matrix(NA,6,1)
> AA
[,1]
[1,] NA
[2,] NA
[3,] NA
[4,] NA
[5,] NA
[6,] NA
> AA[idx,1] <- B
> AA
[,1]
[1,] 10
[2,] NA
[3,] NA
[4,] 20
[5,] 30
[6,] 40
>
In the case of a array, we miss the elements (20 and 30) in B corresponding to the
NA's in the index array. In the case of a matrix, 20 and 30 are assigned to the
elements indexed by the indexes following the NA's. Is this a reasonable behavior.
Thanks in advance for explanation.
-MY
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