rfunctionmatrix

How do I multiply elements using conditional statement?

I am very new to R and programming in general, and I need some help. I want to make a function that multiplies all even numbers in a given matrix by 3, for instance in this matrix:

X = matrix(1:9,3,3)

I have tried the replace function like this:

Multiply = function(M) {
 x=M*3
 replace(M, M%%2==0, x)
}

which gives me a result I don't understand. Any help would be much appreciated!

Solution

  • We can create the function as 

    Multiply <- function(M){ i1 <- M%%2 == 0
          M[i1] <- M[i1]*3
          M }