how to find top N descending values in group in dplyr

user_2927983 0
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I have a following dataframe in R

  Serivce     Codes
   ABS         RT
   ABS         RT
   ABS         TY
   ABS         DR
   ABS         DR
   ABS         DR
   ABS         DR
   DEF         RT
   DEF         RT
   DEF         TY
   DEF         DR
   DEF         DR
   DEF         DR
   DEF         DR
   DEF         TY
   DEF         SE
   DEF         SE

What I want is service wise code count in descending order

  Serivce     Codes    Count
   ABS         DR        4
   ABS         RT        2 
   ABS         TY        1
   DEF         DR        4
   DEF         RT        2
   DEF         TY        2

I am doing following in r

df%>% 
group_by(Service,Codes) %>% 
summarise(Count = n()) %>%
top_n(n=3,wt = Count) %>% 
arrange(desc(Count)) %>% 
as.data.frame()

But,it does not give me what is intended.

r
3 Answers

df%>% count(Service,Codes) %>% mutate(rank = dense_rank(desc(n))) %>% filter(rank < 5)

number of rows to return for top_n() just like row_number()

n is group by Service,Codes then count like

user_63205480
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