Find duplicated rows (based on 2 columns) in Data Frame in R

Question

I have a data frame in R which looks like:

| RIC    | Date                | Open   |
|--------|---------------------|--------|
| S1A.PA | 2011-06-30 20:00:00         


        

Answer 1

Here's a dplyr option for tagging duplicates based on two (or more) columns. In this case ric and date:

df <- data_frame(ric = c('S1A.PA', 'ABC.PA', 'EFG.PA', 'S1A.PA', 'ABC.PA', 'EFG.PA'),
                 date = c('2011-06-30 20:00:00', '2011-07-03 20:00:00', '2011-07-04 20:00:00', '2011-07-05 20:00:00', '2011-07-03 20:00:00', '2011-07-04 20:00:00'),
                 open = c(23.7, 24.31, 24.495, 24.23, 24.31, 24.495))

df %>% 
  group_by(ric, date) %>% 
  mutate(dupe = n()>1)
# A tibble: 6 x 4
# Groups:   ric, date [4]
  ric    date                 open dupe 
                    
1 S1A.PA 2011-06-30 20:00:00  23.7 FALSE
2 ABC.PA 2011-07-03 20:00:00  24.3 TRUE 
3 EFG.PA 2011-07-04 20:00:00  24.5 TRUE 
4 S1A.PA 2011-07-05 20:00:00  24.2 FALSE
5 ABC.PA 2011-07-03 20:00:00  24.3 TRUE 
6 EFG.PA 2011-07-04 20:00:00  24.5 TRUE