Concatenate rows based on group by a column value

Question

I have a data which i need to group on column ID and then concatenate the rows in R studio.

Could anyone please help?

Current Data

ID   Name   Diagnosis    Medicine
1    A      a            a
1    A      b            a
1    A      c            b 
2    B      d            b
2    B      e            c
3    C      f            d

Result Expected

ID   Name   Diagnosis    Medicine
1    A      a|b|c         a|a|b
2    B      d|e           b|c
3    C      f             d

Code written till now is diagnoses<-read_xlsx("excel file.xlsx")

diagnoses <-diagnoses[,c( "ID" ,"Name" ,"Diagnosis" ,"Medicine"),] head(diagnoses)

aggregate(cbind(Diagnosis, Medicine)~ID, df, paste0, collapse = '|') write.xlsx(diagnoses, "Diagnoses.xlsx")

I am getting error :( Please help