Using purrr::pmap within mutate to create list-column

Question

I understand how to use map to iterate over arguments in a df and create a new list column.

For example,

params <- expand.grid(param_a = c(2, 4,          


        

Answer 1

We could try

f1 <- function(x, y, ...) rep(5, x)*y

df.preprocessed <- dplyr::as.tbl(params) %>%
        dplyr::mutate(test_var = purrr::pmap(list(x = param_a
                                 ,y = param_b
                                 ,z = param_c
                                 ,u = param_d),f1
    )
   )
df.preprocessed
# A tibble: 36 x 5
#   param_a param_b param_c param_d  test_var
#                  
# 1       2       3      50       1 
# 2       4       3      50       1 
# 3       6       3      50       1 
# 4       2       6      50       1 
# 5       4       6      50       1 
# 6       6       6      50       1 
# 7       2       9      50       1 
# 8       4       9      50       1 
# 9       6       9      50       1 
#10       2       3     100       1 
# ... with 26 more rows