R: retrieving individuals with given condition in the same date

September 20, 2022

I have the following data

df = id Date Medication
1  2020-02-10     A       
1  2020-02-10     B       
1  2020-03-10     C         
2  2020-05-30     A          
2  2020-05-10     B            
2  2020-05-10     C
3  2020-07-10     A
3  2020-07-10     B
3  2020-07-10     C
4  2020-09-01     A
4  2020-09-10     B
4  2020-09-10     C

I would like to extract those unique individuals with medication A and B on the same date. In this example, would be only id 1 (A and B given on the 2020-02-10) and 3 (A and B given on the 2020-05-10).

Thanks in advance

>Solution :

We could do

library(dplyr)
df %>%
   group_by(Date) %>%
   filter(all(c("A", "B") %in%  Medication), Medication %in% c("A", "B")) %>% 
   ungroup

-output

# A tibble: 4 × 3
     id Date       Medication
  <int> <chr>      <chr>     
1     1 2020-02-10 A         
2     1 2020-02-10 B         
3     3 2020-07-10 A         
4     3 2020-07-10 B