Ash help

weighted_sum.R

weighted_count <- function(data, weights, ...) {
  group_ <- enquos(...)
  data %>% 
    group_by(!!!group_) %>% 
    summarise(amount = sum(.data[[weights]]), n = n())
}

iris %>% weighted_count("Petal.Length", Species)
## A tibble: 3 x 3
#   Species    amount     n
#   <fct>       <dbl> <int>
# 1 setosa       73.1    50
# 2 versicolor  213      50
# 3 virginica   278.     50