Efficient multiplication of columns in a data frame

Question

I have a large data frame in which I am multiplying two columns together to get another column. At first I was running a for-loop, like so:

for(i in 1:nrow(d         


        

Answer 1

As Blue Magister said in comments,

df$new_column <- df$column1 * df$column2

should work just fine. Of course we can never know for sure if we don't have an example of the data.