Search code examples
rdplyrrow-number

row_number in descending order dplyr

I would like to use row_numbers to output a ranking variable in which the row ranked 1 has the highest vote count, and descending:

df<-tibble(x=letters[1:4], votes=c(30,55,21,12))

If I use row_number I have this output

af%>%mutate(rank=row_number(votes))


# A tibble: 4 x 3
  x     votes  rank
  <chr> <dbl> <int>
1 a        30     3
2 b        55     4
3 c        21     2
4 d        12     1

But my desired output for rank would be 2,1,3,4

Thanks very much.

Solution

  • We could use the rank() function with a - before votes indicating the descending order:

    library(dplyr)

df %>% 
  mutate(rank = rank(-votes))

  x     votes  rank
  <chr> <dbl> <dbl>
1 a        30     2
2 b        55     1
3 c        21     3
4 d        12     4