[R] writing a function to work with dplyr::mutate()

[Jeff Newmiller]

I avoid case_when, so don't complain to me about it. Bert and I both suggested standard evaluation approaches that are very amenable to using lookup tables.

On January 19, 2021 1:51:17 PM PST, Steven Rigatti <sjrigatti using gmail.com> wrote:
>I use case_when a lot - but I have a lot of dynamic tables to treat
>this
>way and case_when has to be hard-coded.
>
>On Tue, Jan 19, 2021 at 3:48 PM Jeff Newmiller
><jdnewmil using dcn.davis.ca.us>
>wrote:
>
>> Second this. There is also the findInterval function, which omits the
>> factor attributes and just returns integers that can be used in
>lookup
>> tables.
>>
>> On January 19, 2021 10:33:59 AM PST, Bert Gunter
><bgunter.4567 using gmail.com>
>> wrote:
>> >If you are willing to entertain another approach, have a look at
>?cut.
>> >By
>> >defining the 'breaks' argument appropriately, you can easily create
>a
>> >factor that tells you which values should be looked up and which
>> >accepted
>> >as is. If I understand correctly, this seems to be what you want. If
>I
>> >have
>> >not, just ignore and wait for a more useful reply.
>> >
>> >Cheers,
>> >Bert
>> >
>> >Bert Gunter
>> >
>> >"The trouble with having an open mind is that people keep coming
>along
>> >and
>> >sticking things into it."
>> >-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>> >
>> >
>> >On Tue, Jan 19, 2021 at 10:24 AM Steven Rigatti
><sjrigatti using gmail.com>
>> >wrote:
>> >
>> >> I am having some problems with what seems like a pretty simple
>issue.
>> >I
>> >> have some data where I want to convert numbers. Specifically, this
>is
>> >> cancer data and the size of tumors is encoded using millimeter
>> >> measurements. However, if the actual measurement is not available
>the
>> >> coding may imply a less specific range of sizes. For instance
>numbers
>> >0-89
>> >> may indicate size in mm, but 90 indicates "greater than 90 mm" ,
>91
>> >> indicates "1 to 2 cm", etc. So, I want to translate 91 to 90, 92
>to
>> >15,
>> >> etc.
>> >>
>> >> I have many such tables so I would like to be able to write a
>> >function
>> >> which takes as input a threshold over which new values need to be
>> >looked
>> >> up, and the new lookup table, returning the new values.
>> >>
>> >> I successfully wrote the function:
>> >>
>> >> translate_seer_numeric <- function(var, upper, lookup) {
>> >>     names(lookup) <- c('old','new')
>> >>     names(var) <- 'old'
>> >>     var <- as.data.frame(var)
>> >>     lookup2 <- data.frame(old = c(1:upper),
>> >>                           new = c(1:upper))
>> >>     lookup3 <- rbind(lookup, lookup2)
>> >>  print(var)
>> >>     res <- left_join(var, lookup3, by = 'old') %>%
>> >>          select(new)
>> >>
>> >>     res
>> >>
>> >> }
>> >>
>> >> test1 <- data.frame(old = c(99,95,93, 8))lup <- data.frame(bif =
>> >c(93, 95,
>> >> 99),
>> >>                   new = c(3, 5, NA))
>> >> translate_seer_numeric(test1, 90, lup)
>> >>
>> >> The above test generates the desired output:
>> >>
>> >>   old1  992  953  934   8
>> >>   new1  NA2   53   34   8
>> >>
>> >> My problem comes when I try to put this in line with pipes and the
>> >mutate
>> >> function:
>> >>
>> >> test1 %>%
>> >>      mutate(varb = translate_seer_numeric(var = old, 90, lup))####
>> >>  Error: Problem with `mutate()` input `varb`.
>> >> x Join columns must be present in data.
>> >> x Problem with `old`.
>> >> i Input `varb` is `translate_seer_numeric(var = test1$old, 90,
>lup)`.
>> >>
>> >> Thoughts??
>> >>
>> >>         [[alternative HTML version deleted]]
>> >>
>> >> ______________________________________________
>> >> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> >> https://stat.ethz.ch/mailman/listinfo/r-help
>> >> PLEASE do read the posting guide
>> >> http://www.R-project.org/posting-guide.html
>> >> and provide commented, minimal, self-contained, reproducible code.
>> >>
>> >
>> >       [[alternative HTML version deleted]]
>> >
>> >______________________________________________
>> >R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> >https://stat.ethz.ch/mailman/listinfo/r-help
>> >PLEASE do read the posting guide
>> >http://www.R-project.org/posting-guide.html
>> >and provide commented, minimal, self-contained, reproducible code.
>>
>> --
>> Sent from my phone. Please excuse my brevity.
>>

-- 
Sent from my phone. Please excuse my brevity.