Create new columns with data of 2 or more events so only one row per variable

Question

I've got a list of participants that are listed multiple times in a column, I want them listed once. They have all completed an event a varying number of times. I need a column with the date for first attempt, second etc with NA if they haven't repeated.

 df
  participant  date
1 a            2020-01-02
2 b            2020-09-25
3 c            2020-09-29
4 d            2020-10-07
5 d            2020-10-07
6 d            2020-11-08
7 a            2020-10-12
8 b            2020-10-13

  participant  date1       event1  date2      event2 date3       event3
1 a            2020-01-02    1     2020-10-12  2      NA          NA
2 b            2020-09-25    1     2020-10-13  2      NA          NA
3 c            2020-09-29    1     NA          NA     NA          NA
4 d            2020-10-07    1     2020-11-07  2      2020-10-08  3

I'd be happy to help if you post a reproducible example... https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example — Bill O'Brien, Apr 15 '21 at 15:51

score 1 · Accepted Answer · answered Apr 15 '21 at 17:36

use this

library(dplyr)
library(tidyr)

df %>% group_by(participant) %>%
  mutate(event = row_number(),
         d3 = row_number()) %>%
  pivot_wider(id_cols = participant, names_from = d3, values_from = c(date, event))

# A tibble: 4 x 7
# Groups:   participant [4]
  participant date_1     date_2     date_3     event_1 event_2 event_3
  <chr>       <chr>      <chr>      <chr>        <int>   <int>   <int>
1 a           2020-01-02 2020-10-12 NA               1       2      NA
2 b           2020-09-25 2020-10-13 NA               1       2      NA
3 c           2020-09-29 NA         NA               1      NA      NA
4 d           2020-10-07 2020-10-07 2020-11-08       1       2       3

Create new columns with data of 2 or more events so only one row per variable

1 Answers1