[英]Apply a replacement to each 3rd dimension of a 3D array
I have an mxnxp (3D) array A. I have a 2D matrix B with values ranging from 1:m in the first column and 1:n in the second column. 我有一个mxnxp(3D)数组A。我有一个2D矩阵B,其值在第一列中为1:m,在第二列中为1:n。 What I'd like to do is NA out the indices that correspond to those given by B in each of the third dimension (heights?).
我想做的是在第三个维度(高度?)的每一个中对应于B给出的索引。 So,
所以,
for (i in 1:p) {
A[,,i][B] = NA
}
Is there a way to do this without a for loop? 有没有没有for循环的方法? I was thinking something like
我在想类似
A_NA = apply(A,3,function(x) x[B] = NA)
But that doesn't work. 但这是行不通的。
We need to return the x
and then assign it back to 'A' 我们需要返回
x
,然后将其分配回'A'
A[] <- apply(A,3,function(x) { x[B] = NA; x})
Checking with the OP's solution 检查OP的解决方案
for (i in 1:p) {
A1[,,i][B] = NA
}
identical(A, A1)
#[1] TRUE
A <- array(1:40, c(5, 4, 2) )
B <- cbind(c(1, 2, 3, 4), c(2, 3, 1, 1))
p <- 2
A1 <- A
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