I have longitudinal patient data in R. I would like to create an end_date variable (4th column in table below) from the three different dates I already have, whichever occurred first, and in case death or transfer didn't occur, end_date would equal to data_collection_end_date:

CodePudding user response：

If the dates are proper date type objects, we can use rowwise() and max(). We may have to transform those into dates in case they are strings.

library(dplyr)

data %>% rowwise() %>%
         mutate(end_date = max(c_across(death_rate:data_collection_end_date), na.rm = TRUE))

CodePudding user response：

Capture whichever occurred first:

library(dplyr)
library(lubridate)

# Your sample data
patid <- c(1:6)
death_date <- dmy(c("07/07/2018", "07/07/2019", "07/07/2020", NA, NA, NA))
transfer_date <- dmy(c("07/07/2016", "07/07/2018", "07/07/2018", NA, NA, "07/09/2016"))
data_collection_end_date <- dmy(c("01/11/2021", "01/11/2021", "01/11/2021", "01/11/2021", "01/11/2021", "01/11/2021"))

# Data frame
df <- data.frame(patid, death_date, transfer_date, data_collection_end_date)



# @GuedesBF's solution corrected to capture earliest date
df %>% rowwise() %>%
  mutate(end_date = min(c_across(death_date:data_collection_end_date), na.rm = TRUE))