问题 I have a data frame as below: df <- data.frame( id = c(1:5), a = c(3,10,4,0,15), b = c(2,1,1,0,3), c = c(12,3,0,3,1), d = c(9,7,8,0,0), e = c(1,2,0,2,2) ) I need to add multiple columns of which names are given by a combination of a:c and 3:5 . 3:5 is also used in sum function: df %>% mutate( usa_3 = sum(1+3), usa_4 = sum(1+4), usa_5 = sum(1+5), canada_3 = sum(1+3), canada_4 = sum(1+4), canada_5 = sum(1+5), nz_3 = sum(1+3), nz_4 = sum(1+4), nz_5 = sum(1+5) ) The result is really simple but I