Allows for the manipulation of a subset of a data.frame based on a predicate. Similar to using `if_else()` inside `mutate()`, but also allows for the use of `across()` style mutations

mutate_where.R

mutate_where <- function(x,predicate,...){
  
  full_x <- mutate(x,..row_ids = 1:n())
  
  .predicate <- enquo(predicate)
  
  predicated_x <- filter(full_x,!!.predicate)
  other_x <- filter(full_x,!(!!.predicate)|is.na(!!.predicate))
  
  mutated_x <- mutate(predicated_x,!!!enquos(...))
  
  return_x_unsorted <- bind_rows(mutated_x,other_x)
  
  return_x_sorted <- arrange(return_x_unsorted,..row_ids)
  
  select(return_x_sorted,-..row_ids)
}