How to generate a matrix based on a values of another matrix in R

Question

Suppose that I have lower triangular matrix ie,

w1 <- c(0,0.6,0.3,0.6,0.7,
    0,0,0.6,0.6,0.7,
    0,0,0,0.6,0.6,
    0,0,0,0,0.7,
    0,0,0,0,0)
w1 <- matrix(w1,5,5)

Then, I would like the second matrix to be a lower triangular matrix, say w2 where each non-zero values of w2 are 1-the corresponding values of w1 .

Like this:

w2 <- c(0,0.4,0.7,0.4,0.3,
    0,0,0.4,0.4,0.3,
    0,0,0,0.4,0.4,
    0,0,0,0,0.3,
    0,0,0,0,0)
w2 <- matrix(w2,5,5) 
w <- list(w1, w2)

How can I get w2 automatically?

Answer 1

由于R中的大多数运算都是矢量化的，因此您可以简单地使用ifelse减去1 - w1 ，或者如果w1为零，则保留零。

ifelse(w1 == 0, 0, 1 - w1)

Answer 2

You can use the indexing of lower.tri() also on the left side:

w2new <- matrix(0, dim(w1)[1], dim(w1)[2])
w2new[lower.tri(w2new)] <- 1 - w1[lower.tri(w1)]