dplyr - Group by and select TOP x %

Question

Using the package dplyr and the function sample_frac it is possible to sample a percentage from every group. What I need is to first sort the elements in every

Answer 1

A slight variation using top_n and dplyr:

mtcars %>% 
 group_by(gear) %>% 
 select(gear, wt) %>% 
 arrange(gear) %>% 
 top_n(seq(n()*.2))

  gear    wt
   
1     3  5.42
2     3  5.34
3     3  5.25
4     4  3.44
5     4  3.44
6     5  3.57