gdata (version 3.0.0)

upperTriangle: Extract or replace the upper/lower triangular portion of a matrix

Description

Extract or replace the upper/lower triangular portion of a matrix.

Usage

upperTriangle(x, diag=FALSE, byrow=FALSE)
upperTriangle(x, diag=FALSE, byrow=FALSE) <- value
lowerTriangle(x, diag=FALSE, byrow=FALSE)
lowerTriangle(x, diag=FALSE, byrow=FALSE) <- value

Value

upperTriangle(x) and lowerTriangle(x) return the upper or lower triangle of matrix x, respectively. The assignment forms replace the upper or lower triangular area of the matrix with the provided value(s).

Arguments

x

Matrix

diag

Logical. If TRUE, include the matrix diagonal.

byrow

Logical. If FALSE, return/replace elements in column-wise order. If TRUE, return/replace elements in row-wise order.

value

Either a single value or a vector of length equal to that of the current upper/lower triangular. Should be of a mode which can be coerced to that of x.

Author

Gregory R. Warnes

See Also

diag, lower.tri, upper.tri

Examples

x <- matrix(1:25, nrow=5, ncol=5)
x
upperTriangle(x)
upperTriangle(x, diag=TRUE)
upperTriangle(x, diag=TRUE, byrow=TRUE)

lowerTriangle(x)
lowerTriangle(x, diag=TRUE)
lowerTriangle(x, diag=TRUE, byrow=TRUE)

upperTriangle(x) <- NA
x

upperTriangle(x, diag=TRUE) <- 1:15
x

lowerTriangle(x) <- NA
x

lowerTriangle(x, diag=TRUE) <- 1:15
x

## Copy lower triangle into upper triangle to make
## the matrix (diagonally) symmetric
x <- matrix(LETTERS[1:25], nrow=5, ncol=5, byrow=TRUE)
x
lowerTriangle(x) = upperTriangle(x, byrow=TRUE)
x