library(tidyverse)
sample_n_of <- function(data, size, ...) {
dots <- quos(...)
group_ids <- data %>%
group_by(!!! dots) %>%
group_indices()
sampled_groups <- sample(unique(group_ids), size)
data %>%
filter(group_ids %in% sampled_groups)
}
set.seed(1234)
mpg %>%
group_by(model) %>%
slice_sample(n = 2) %>%
ungroup()
#> # A tibble: 76 x 11
#> manufacturer model displ year cyl trans drv cty hwy fl class
#> <chr> <chr> <dbl> <int> <int> <chr> <chr> <int> <int> <chr> <chr>
#> 1 toyota 4runner~ 2.7 1999 4 manual~ 4 15 20 r suv
#> 2 toyota 4runner~ 3.4 1999 6 manual~ 4 15 17 r suv
#> 3 audi a4 2.8 1999 6 auto(l~ f 16 26 p comp~
#> 4 audi a4 2 2008 4 auto(a~ f 21 30 p comp~
#> 5 audi a4 quat~ 3.1 2008 6 auto(s~ 4 17 25 p comp~
#> 6 audi a4 quat~ 2.8 1999 6 auto(l~ 4 15 25 p comp~
#> 7 audi a6 quat~ 2.8 1999 6 auto(l~ 4 15 24 p mids~
#> 8 audi a6 quat~ 4.2 2008 8 auto(s~ 4 16 23 p mids~
#> 9 nissan altima 2.5 2008 4 manual~ f 23 32 r mids~
#> 10 nissan altima 2.5 2008 4 auto(a~ f 23 31 r mids~
#> # ... with 66 more rows
mpg %>%
sample_n_of(size = 2, model)
#> # A tibble: 12 x 11
#> manufacturer model displ year cyl trans drv cty hwy fl class
#> <chr> <chr> <dbl> <int> <int> <chr> <chr> <int> <int> <chr> <chr>
#> 1 audi a6 qua~ 2.8 1999 6 auto(l~ 4 15 24 p midsi~
#> 2 audi a6 qua~ 3.1 2008 6 auto(s~ 4 17 25 p midsi~
#> 3 audi a6 qua~ 4.2 2008 8 auto(s~ 4 16 23 p midsi~
#> 4 ford mustang 3.8 1999 6 manual~ r 18 26 r subco~
#> 5 ford mustang 3.8 1999 6 auto(l~ r 18 25 r subco~
#> 6 ford mustang 4 2008 6 manual~ r 17 26 r subco~
#> 7 ford mustang 4 2008 6 auto(l~ r 16 24 r subco~
#> 8 ford mustang 4.6 1999 8 auto(l~ r 15 21 r subco~
#> 9 ford mustang 4.6 1999 8 manual~ r 15 22 r subco~
#> 10 ford mustang 4.6 2008 8 manual~ r 15 23 r subco~
#> 11 ford mustang 4.6 2008 8 auto(l~ r 15 22 r subco~
#> 12 ford mustang 5.4 2008 8 manual~ r 14 20 p subco~Created on 2021-03-24 by the reprex package (v0.3.0)