R/monthly_mean.R

In HARPgroup/cbp6:

#' Monthly Mean Metric Function
#' @description Measures monthly mean of dataframe - data must be trimmed to water year
#' @param data dataframe of date and flow data taken from import data functions
#' @param num.month number for month of interest
#' @return monthly mean metric
#' @import lubridate
#' @import stats
#' @export monthly_mean

monthly_mean <- function(data, num.month) {
  # Setup for Monthly Means Calculations
  data$year <- year(ymd(data$date))
  data$month <- month(ymd(data$date))
  data$day <- day(ymd(data$date))
  monthly_means <- aggregate(data$flow, list(data$month), FUN = mean)
  mean_flows <- monthly_means[num.month,2]
  return(mean_flows)
}