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rmultiple-columnsframe

Operations on multiple columns accross many tables

I have two tables (dt1, dt2). dt2 contains the same variables names as dt1. For each variable in dt1 I would like to multiply it with its values from dt2. In the exemple below, x from dt1 will get multiplied with 4 and y with 7. How would be the fast way to do it? Thank you

  set.seed(123)
  dt1 <- data.frame(x = sample(1:10, 10, TRUE), y = sample(1:10, 10, TRUE) )
  dt1
  dt2 = data.frame (names = c("x", "y"), values = c(4, 7))
  dt2
Solution

  • purrr style

    map2_df(dt1, dt2 %>% pivot_wider(names_from = names, values_from = values), ~.y * .x)

# A tibble: 10 x 2
       x     y
   <dbl> <dbl>
 1    12    35
 2    12    21
 3    40    63
 4     8    63
 5    24    63
 6    20    21
 7    16    56
 8    24    70
 9    36    49
10    40    70