at: Set or get matrix value at index vector
In matricks: Useful Tricks for Matrix Manipulation

Description Usage Arguments Value Examples

This function allows to access matrix values by passing indices as vector

1
2
3

at(mat, idx)

at(mat, idx) <- value

`mat`	matrix
`idx`	two-element integer vector
`value`	a value to be assign at index

'at' function: value from matrix at index idx

mat <- matrix(0, 3, 3)
idx <- c(1, 2)
# Typically, given matrix and row-column indices as two-element vector, we should do it like this:
mat[idx[1], idx[2]]
mat[idx[1], idx[2]] <- 8
# Using `at`, we can do it simplier!
at(mat, idx)
at(mat, idx) <- 7
mat
at(mat, idx)