R/year_spp_delta.R

In peterkuriyama/ch4:

#' Function to calculate values for delta plots
#' Skew and proportion of zeroes specifically

#' @param year Year to focus on
#' @param skew Skew of non-zero, logged pound values

#' @export

year_spp_delta <- function(year, spp){
  tt <- tows_clust %>% filter(set_year == year) 
  all_tows <- tt %>% distinct(haul_id)
  
  spp_catch <- tt %>% filter(species == spp) %>% select(haul_id, apounds)
  the_tows <- all_tows %>% left_join(spp_catch, by = 'haul_id')
  the_tows[which(is.na(the_tows$apounds)), 'apounds'] <- 0
  
  zeroes <- the_tows %>% filter(apounds == 0) %>% nrow 
  prop_zero <- zeroes / nrow(the_tows)
  
  skew <- calc_skew(log(subset(the_tows, apounds != 0)$apounds))
  
  return(data.frame(species = spp, year = year, prop_zero = prop_zero, skew = skew))
}