R/flag_frequency.R

In flagr: Implementation of Flag Aggregation

#' Flag aggregation by the frequency count method
#'
#' @param f A vector of flags containing the flags of a series for a given period.
#' @return \code{flag_frequency} returns a character with a single character flag in case the highest frequency count
#'  is unique, or multiple character in case there are several flags with the highest frequency count.
#' @examples
#' flag_frequency(c("pe","b","p","p","u","e","d"))
#' flag_frequency(c("pe","b","p","p","eu","e","d"))
#'
#' 
#' flags <- tidyr::spread(test_data[, c(1:3)], key = time, value = flags)
#' flag_frequency(flags[,5])
#' apply(flags[, c(2:ncol(flags))],2, flag_frequency)
#'
#' @export

flag_frequency<-function(f){
  f<-f[!is.na(f)]
  if (length(f)==0){
    return(NA)
  }else{
    f<-strsplit(paste0(f,collapse = ""),split = "")[[1]]
    max_count<-(sort(table(f),decreasing=T)[1])
    names(sort(table(f),decreasing=T)[sort(table(f),decreasing=T)==max_count])
  }
}