How to sample elements in a list nested within a tibble?

Question

a = tribble(~i,~k,
            c(1,2,3),2) %>%
  mutate(picks = sample(i,k))

I want to sample k elements within i, but mutate thinks that I want to sample i as singular element.

Answer 1

You were close; just need to add in rowwise and wrap sample in list().

library(tidyverse)

a = tribble(~i,~k,
            c(1,2,3),2) %>%
  rowwise %>% 
  mutate(picks = list(sample(i,k)))

a

#  i             k picks    
#  <list>    <dbl> <list>   
#1 <dbl [3]>     2 <dbl [2]>