select_random

select_random <- function(tbl, n_records) {
  tbl <- tbl %>%
    dplyr::mutate(rand = random()) %>%
    dplyr::compute() %>%
    dplyr::arrange(.data$rand) %>%
    dplyr::filter(dplyr::row_number(.data$rand) <= !!n_transactions) %>%
    dplyr::select(-.data$rand)
}

tbl %>% 
  group_by(var) %>% 
  select_random(10)