> # base > dat <- data.frame(a = c(10, 11, 12), + b = c(4, 5, 6), + colour = c("blue", "green", "yellow"), + stringsAsFactors = FALSE) > dat$c <- 2 * dat$a > dat$sum <- dat$a + dat$b > > # dplyr > dat <- data_frame(a = c(10, 11, 12), + b = c(4, 5, 6), + colour = c("blue", "green", "yellow")) %>% + mutate(c = 2 * a, + sum = a + b)