[R] Filtering based on the occurrence

[Farnoosh Sheikhi]

Hello, 
I have a data set similar to below and I wanted to keep the observations after the first occurrence of these department: "B", "D", "F".For example for ID=2, the observation with deps=B and anything after will be kept in the data. For ID=3, observations with deps=D and anything after will be included.
Subject<- c("2", "2", "2", "3", "3", "3", "4", "4", "5", "5", "5", "5")dates<-seq(as.Date('2011-01-01'),as.Date('2011-01-12'),by = 1) deps<-c("A", "B", "C", "C", "D", "A", "F", "G", "A", "F", "A", "D")df <- data.frame(Subject, dates, deps)df
The final data should look like this:final<-c("2 2011-01-02    B","2 2011-01-03    C","3 2011-01-05    D","3 2011-01-06    A","4 2011-01-07    F","4 2011-01-08    G","5 2011-01-10    F","5 2011-01-11    A","5 2011-01-12    D") Thank you tons for your help. 
Farnoosh


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