track        type    shortcut player  system_played date       time_period  time record_duration
   <chr>        <chr>   <chr>    <chr>   <chr>         <date>     <chr>       <dbl>           <dbl>
 1 Luigi Racew~ Three ~ No       Salam   NTSC          1997-02-15 2M 12.99S   133.                1
 2 Luigi Racew~ Three ~ No       Dan     PAL           2020-11-06 1M 57.77S   118.              112
 3 Moo Moo Farm Three ~ No       Gregg G NTSC          1997-03-07 1M 35.48S    95.5              81
 4 Moo Moo Farm Three ~ No       MR      PAL           2020-02-18 1M 25.93S    85.9             374
 5 Koopa Troop~ Three ~ No       Launsp~ NTSC          1997-05-27 1M 42.01S   102.               95
 6 Koopa Troop~ Three ~ No       Dan     PAL           2020-07-13 1M 35.29S    95.3               0

I have a dataset as above, and now I want to replace the column "date" with a new column "newdate" that contains the SAME values but under DIFFERENT names. For each "track", the earliest "date" will become "First", and the latest date will become "Last".
I tried this code:

mydata <- data %>%
  group_by(track) %>%
  mutate(newdate = recode(date, "First", .default = "Last"))

And encountered an error message:

Error: Problem with mutate() input newdate. x no applicable method for 'recode' applied to an object of class "Date" i Input newdate is recode(date, "First", .default = "Last"). i The error occurred in group 1: track = "Banshee Boardwalk".

Is there an alternative function for recode() that could apply for "Date" class values?

CodePudding user response：

If we want to change the min and max date to character elements, we need to first convert the date from Date class to character

library(dplyr)
mydata <- data %>%
       group_by(track) %>%
       mutate(newdate = case_when(date == min(date) ~ "First",
                       date == max(date) ~ "Last", TRUE ~ as.character(date)))