lower.tri {base} R Documentation

## 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?

diag, matrix; further row and col on which lower.tri() and upper.tri() are built.
(m2 <- matrix(1:20, 4, 5))