Lens into upper diagonal elements

Create a lens into the upper diagonal elements of a matrix

upper_tri_l(diag = FALSE)

Arguments

diag	whether or not to include the diagonal (x <- matrix(1:9, ncol = 3)) view(x, upper_tri_l()) view(x, upper_tri_l(diag = TRUE)) set(x, upper_tri_l(), c(100, 200, 300))