Multiply columns across

[davidodongo]

Hello,

I have columns a,b,c,x,y,z and would like to create new columns by multiplying ax, by and c*z

library(tidyverse)

(mytable <- data.frame(
  a=1:2,
  b=2:3,
  c=3:4,
  x=5:6,
  y=7:8,
  z=9:10
))

How would I go about this in R?
thank you

[Leon]

Try this:

mytable |>
  as_tibble() |>
  mutate(ax = a*x,
         by = b*y,
         cz = c*z)

[davidodongo]

thanks....how about if i want to do it for very many column pairs i.e 30, is there an easier way to handle it

[nirgrahamuk]

library(tidyverse)
library(rlang)
(mytable <- data.frame(
  a=1:2,
  b=2:3,
  c=3:4,
  x=5:6,
  y=7:8,
  z=9:10
))
ncm <- ncol(mytable)
(first_cols <- seq_len(ncm/2))
(second_cols <- setdiff(seq_len(ncm),first_cols))
first_half_names <- names(mytable)[first_cols]
second_half_names <- names(mytable)[second_cols]

(step_1 <- map2(first_half_names,
                second_half_names,
                \(x,y) paste0(x,"*",y) ))
(step_2 <- map2(first_half_names,
                second_half_names,
                \(x,y) paste0(x,y) ))

(step_3 <- rlang::parse_exprs(paste0(step_1,collapse=";")))
names(step_3) <- step_2
step_3

mutate(mytable,
       !!!(step_3))