CODEWITHSUNDEEP
rdplyr
zesla
zesla

Reputation: 11833

filter rows within groups after group_by in dplyr

I have a dataframe like below. Some of the subject/variable group do not have D1 in visit. What I need to do is filter those rows. In other word, I need to extract only those groups that contains D1 in visit. Appreciate it if anyone can help with this. 

dt = expand.grid(subject=1:3,
                 variable = c('A', 'B', 'C'),
                 visit = c('D1', 'D2', 'D3'))
dt <- dt %>% filter(!(variable=='C'&visit=='D1'))

dt %>% 
    group_by(subject, variable) %>% 
    arrange(subject, variable) %>%
    ?????

Upvotes: 1

Views: 128

Answers (2)

iod
iod

Reputation: 7592

You can use any:

dt %>% 
  group_by(subject, variable) %>% 
  filter(any(visit=="D1"))

Upvotes: 1

akrun
akrun

Reputation: 887891

We can use %in%

dt %>% 
   group_by(subject, variable) %>% 
   filter('D1' %in% visit)

Upvotes: 2

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