| lower.tri {base} | R Documentation |
Lower and Upper Triangular Part of a Matrix
Usage
lower.tri(x, diag=FALSE)
upper.tri(x, diag=FALSE)
Arguments
x |
a matrix. |
diag |
logical. Should the diagonal be included? |
Value
Returns a logical matrix of the same dimension as
x which is TRUE for the relevant triangular part of x.
See Also
diag, matrix.
Examples
m2 <- ma <- matrix(1:20, 4, 5)
m2[lower.tri(m2)] <- NA
m2
all(lower.tri(ma) == !upper.tri(ma, diag=TRUE))