R/trend_line.R

In aidaylanan/SAfeR: Visualization tools for SA Crime Stats

#' Create a trend line of all the crime rates in a specific geographic area
#'
#' @param station A valid station in the crime data frame, string
#'
#' @return A visualization of all the crime rates in a specific Station and Category
#' @export
#' @examples
#' trend_line("Cape Town Central")
#' trend_line("Aberdeen")
#'
trend_line <- function(station) {
  s1 <- sprintf("^%s$", station) #to error check for an exact match
  if  (any(grepl(s1, crime[,2])))  {
    cate <- select_category(station)
    ggplot((crime[which(crime$Station == station & crime$Category == cate), ]), aes(x=Year, y=Crime_Rate)) +
      geom_point() +
      geom_line(group=1)
  }
  else {
    stop("Please type in valid station.")
  }
}