matrixStats (version 0.12.2)

indexByRow: Translates matrix indices by rows into indices by columns

Description

Translates matrix indices by rows into indices by columns.

Usage

indexByRow(dim, idxs=NULL, ...)

Arguments

dim

A numeric vector of length two specifying the length of the "template" matrix.

idxs

A vector of indices. If NULL, all indices are returned.

...

Not use.

Value

• Returns an integer vector of indices.

Examples

dim <- c(5, 4)
X <- matrix(NA_integer_, nrow=dim[1], ncol=dim[2])
Y <- t(X)
idxs <- seq(along=X)

# Assign by columns
X[idxs] <- idxs
print(X)

# Assign by rows
Y[indexByRow(dim(Y), idxs)] <- idxs
print(Y)

stopifnot(X == t(Y))