Pull value from different column that is paired with first value-CodePudding

I have patient follow-up visits - each patient has several visits, and are missing data from some visits. I'm pulling the value from the first visit that has non-missing data (i.e. their earliest follow-up with data).

How could I also pull the date that goes along with that first non-missing data value? (All patients have the date filled in, regardless of if the value was missing)

sample data:

library(tibble)
library(dplyr)

data <- tribble(
  ~PatientID, ~Visit_Date, ~Status,
  155, "15-Mar-2016", NA,
  155, "20-Apr-2017", 2040,
  155, "09-May-2018", 2050,
  200, "04-Apr-2004", NA,
  200, "10-Jun-2005", NA,
  200, "07-Jul-2006", 2080
)

I'm thinking the code will go something like

data %>%
  group_by(PatientID) %>%
  mutate(first_status = dplyr::first(na.omit(Status))) %>%
  mutate(first_date = ___________)

Desired output:

tribble(
  ~PatientID, ~Visit_Date, ~Status, ~first_status, ~first_date,
  155, "15-Mar-2016", NA, 2040, "20-Apr-2017",
  155, "20-Apr-2017", 2040, 2040, "20-Apr-2017",
  155, "09-May-2018", 2050, 2040, "20-Apr-2017",
  200, "04-Apr-2004", NA, 2080, "07-Jul-2006",
  200, "10-Jun-2005", NA, 2080, "07-Jul-2006",
  200, "07-Jul-2006", 2080, 2080, "07-Jul-2006",
)

CodePudding user response：

We may use complete.cases or is.na to get the logical vector for subsetting (assuming Visit_Date is ordered by 'PatientID')

library(dplyr)
data %>%
   group_by(PatientID) %>%
   mutate(first_status = Status[!is.na(Status)][1], 
          first_date = Visit_Date[!is.na(Status)][1]) %>%
   ungroup

-output

# A tibble: 6 × 5
  PatientID Visit_Date  Status first_status first_date 
      <dbl> <chr>        <dbl>        <dbl> <chr>      
1       155 15-Mar-2016     NA         2040 20-Apr-2017
2       155 20-Apr-2017   2040         2040 20-Apr-2017
3       155 09-May-2018   2050         2040 20-Apr-2017
4       200 04-Apr-2004     NA         2080 07-Jul-2006
5       200 10-Jun-2005     NA         2080 07-Jul-2006
6       200 07-Jul-2006   2080         2080 07-Jul-2006