sum two columns in R

Question

I feel a bit embarrassed as I am trying to add two columns in R to get the product.

I have tried

sum(col1,col2)

but this returns

Answer 1

You can use a for loop:

for (i in 1:nrow(df)) {
   df$col3[i] <- df$col1[i] + df$col2[i]
}