R/above_Or_below_Line.R

In msxakk89/dat: Data Analyst Toolkit (dat): a library of tools for data analysts and scientists

#' Is a data point above or below a line described by a linear mathematical formula?
#'
#' This function assesses whether a given data point is above or below a stright line described by mathematical formula.
#'
#' @param point_coord A numeric vector of point coordinates on 2D plane. Following math convention point_coord[1] is the value on X axis, while point_coord[2] is the value on Y axis.
#' @param m A single numeric of the slope.
#' @param b A single numeric of the intercept.
#' @param above A boolean indicating whether to test if the point is above or below the line. 
#' @export

above_Or_below_Line <- function(point_coord=NA, m=0, b=0, above=TRUE) {
  # Is the first number of input 'point_coord' vector an X coordinate? Is the second number of input 'point_coord' a Y coordinate? Make sure it is the case!
  y <- m*point_coord[1]+b
  if(y<point_coord[2]){
    out <- TRUE
  }
  else{
    out <- FALSE
  }
  if(above==TRUE){
    return(out)
  }
  else{
    return(!(out))
  }
  print("DONE")
}