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

I know this is coming late, but might help someone now. dplyr has a new function top_frac

  library(dplyr)
mtcars %>%
  select(gear, wt) %>%
  group_by(gear) %>%
  arrange(gear, wt) %>%
  top_frac(n = 0.2,wt = wt)

Here n is the fraction of rows to return and wt is the variable to be used for ordering.

The output is as below.

gear wt 3 5.250 3 5.345 3 5.424
4 3.440 4 3.440 5 3.570