Adding a new row in a dataframe

Question

Given a dataframe

category <- c("A", "B", "C")
r1 <- c(2, 2, 2)
r2 <- c(3, 3, 3)
r3 <- c(1, 1, 1)
r4 <- c(4, 4, 4)
df <- data.frame(category, r1, r2, r3, r4)

How do I calculate and add a new row D by multiplying values in A and B per column and dividing by the sum of C?

Are you sure you want to add a new row? Or do you mean a new column? Because values that belong together should be in the same row not in the same column. — tamara d, Jul 31 '20 at 08:01

score 0 · Answer 1 · answered Jul 30 '20 at 23:08

0

Perhaps we can do

 df$r5 <- (df$r2 * df$r4)/sum(df$r4)

answered Jul 30 '20 at 23:08

akrun

1 Answers1