Using mutate() in a function with the new colname as an argument

tidyverse
6

It occurs to me that another benefit of the lookup table alternative I suggested over in the other thread is that it also happens to allow you to sidestep the non-standard evaluation business:

library(tidyverse)

# Setup example data
mrgb_trus <- data.frame(
  MRGB_gleason = c("3+4", "4", "3+4", "4+4", "3+3",NA, "3+4", "3+3", NA, "4+3", 
                   "3+3", "3+4", "3+4", NA, "3", "3+4", NA, NA, NA, NA, "4+3", "3+4", "3+3", 
                   "4+3", "4+4", "4+5", "3+3", "4+3", "4+3", NA, NA, "3+3", "4+4", "3+4", "4+5", 
                   "3+3", "5+4", NA, NA, "3+4", "4+3", NA, "3+3", "4+3", "3+4", "3+4", "3+4", NA, 
                   "4+4", "4+3", "3+4", "3+4"), 
  stringsAsFactors = FALSE)

mrgb_lookup <- data.frame(
  gleas_score   = c("5+4", "5+5", "4+5", "4+4", "4+3", "3+4", "3+3", "3", "4", NA ),
  gleas_grd_grp = c(  "5",   "5",   "5",   "4",   "3",   "2",   "1", "1", "1", "0"),
  stringsAsFactors = FALSE
)

gs_to_ggg <- function(df, lookup, colname_gs, colname_ggg) {
  # Build the `by` parameter: 
  #   - Gleason scores should be in the first col of lookup table
  #   - `colname_gs` should contain the name of the Gleason score
  #      variable in `df`
  join_by <- names(lookup)[1]
  names(join_by) <- colname_gs
  
  df <- df %>% inner_join(lookup, by = join_by)
  
  # The last column added to df will be the Gleason Grade Groups
  # from the lookup table; rename it to value of `colname_ggg`
  names(df)[length(df)] <- colname_ggg
  df
}

mrgb_trus %>% 
  gs_to_ggg(
    mrgb_lookup, 
    colname_gs = "MRGB_gleason",
    colname_ggg = "MRGGG"
  ) %>% 
  head(20)
#>    MRGB_gleason MRGGG
#> 1           3+4     2
#> 2             4     1
#> 3           3+4     2
#> 4           4+4     4
#> 5           3+3     1
#> 6          <NA>     0
#> 7           3+4     2
#> 8           3+3     1
#> 9          <NA>     0
#> 10          4+3     3
#> 11          3+3     1
#> 12          3+4     2
#> 13          3+4     2
#> 14         <NA>     0
#> 15            3     1
#> 16          3+4     2
#> 17         <NA>     0
#> 18         <NA>     0
#> 19         <NA>     0
#> 20         <NA>     0

Created on 2018-07-03 by the reprex package (v0.2.0).

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