lower.tri {base}

Lower and Upper Triangular Part of a Matrix

Description

Returns a matrix of logicals the same size of a given matrix with entries TRUE in the lower or upper triangle.

Usage

lower.tri(x, diag = FALSE)
upper.tri(x, diag = FALSE)

Arguments

x

a matrix or other R object with length(dim(x)) == 2. For back compatibility reasons, when the above is not fulfilled, as.matrix(x) is called first.

diag

logical. Should the diagonal be included?

See Also

diag, matrix; further row and col on which lower.tri() and upper.tri() are built.

Examples

(m2 <- matrix(1:20, 4, 5))
lower.tri(m2)
m2[lower.tri(m2)] <- NA
m2