Help with Collapsing and Reshaping Data Frame

[williaml]

You should provide a reproducible example so that it is easier to provide you with an answer.

FAQ: What's a reproducible example (`reprex`) and how do I create one?

Why reprex? Getting unstuck is hard. Your first step here is usually to create a reprex, or reproducible example. The goal of a reprex is to package your code, and information about your problem so that others can run it and feel your pain. Then, hopefully, folks can more easily provide a solution. What's in a Reproducible Example? Parts of a reproducible example: background information - Describe what you are trying to do. What have you already done? complete set up - include any library() calls and data to reproduce your issue. data for a reprex: Here's a discussion on setting up data for a reprex make it run - include the minimal code required to reproduce your error on the data…

But anyway, I assume that it looks like this with the first column being a row number?

library(tidyverse)
df <- tibble::tribble(
  ~row, ~transplantid, ~drugcode, ~monthcode,
    1L,           76L,       "P",  "Initial",
    2L,           76L,       "V",  "Initial",
    3L,           76L,       "X",  "Initial",
    4L,           76L,       "P",    "3 Mth",
    5L,           76L,       "V",    "3 Mth",
    6L,           76L,       "X",    "3 Mth",
    7L,           77L,       "P",  "Initial"
  )

But then how do you get from here to the second bit? Where does VXU come from?