R/seasonal_median.R

In donco/odeqtmdl: Oregon TMDL database

#' Create seasonal median values for a dataset
#'
#' Takes a dataframe from which_target_df(), calculates the seasonal median results, and returns the dataframe with only
#' seasonal median results
#' @param df A dataframe with values provided by which_target_df()
#' @return The dataframe consisting of calculated seasonal medians
#' @export
#' @examples
#' seasonal_median(df)

seasonal_median <- function(df){

df <- df %>%
  dplyr::filter(tmdl_season) %>%
  dplyr::group_by_at(vars(-Project1, -Result, -Result_Numeric, -Result_Operator, -Result_Unit, -Result_cen,
                          -Statistical_Base, -DQL, -Method_Code, -Activity_Type, -act_id, -MRLValue,
                          -Result_status, -sample_datetime, -sample_id, -Spawn_type, -spawn_start, -spawn_end)) %>%
  dplyr::summarise(seasonal_median = median(Result_cen, na.rm = TRUE),
                   sample_datetime = first(start_datetime)) %>%
  dplyr::ungroup() %>%
  dplyr::mutate(Result_cen = seasonal_median)

return(df)

}