row {base}R Documentation

Row Indexes

Description

Returns a matrix of integers indicating their row number in the matrix.

Usage

row(x, as.factor = FALSE)

Arguments

x a matrix.
as.factor a logical value indicating whether the value should be returned as a factor rather than as numeric.

Value

An integer matrix with the same dimensions as x and whose ij-th element is equal to i.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

col to get columns.

Examples

x <- matrix(1:12, 3, 4)
# extract the diagonal of a matrix
dx <- x[row(x) == col(x)]
dx

# create an identity 5-by-5 matrix
x <- matrix(0, nr = 5, nc = 5)
x[row(x) == col(x)] <- 1
x
[Package Contents]