How do you write a ECDF function for an arbitrary dataset

squareCDF.R

#!/usr/bin/env/Rscript
squareCDF <- function(n=100){
  # create random data
  user_id <- seq(1,n)
  payment_id <- seq(101,n+100)
  payment_amount <- rnorm(n, mean= 100, sd=50)
  is_card_present <- sample(0:1, n, replace=T)
  data <- data.frame(user_id, payment_id, payment_amount, is_card_present)

  # calculate ECDF
  less100 <- subset(data, payment_amount < 100)
  more100 <- subset(data, payment_amount > 100)
  sortedless <- sort(less100$is_card_present)
  sortedmore <- sort(more100$is_card_present)
  less_nrow <- nrow(less100)
  more_nrow <- nrow(more100)
  ecdfless <- (1:less_nrow)/less_nrow
  ecdfmore <- (1:more_nrow)/more_nrow

  # function for returning area left of percentile
  cp <- function(percentile, dataPassed){
    n <- length(dataPassed)
    numerator <- length(dataPassed[dataPassed == 0])
    if (percentile * .01 < 1){
      return(numerator/n)
    } else {
      return(1)
    }
  }

  # print ECDFs in text format
  print("Users who processed less than $100")
  print("percentile % cp")
  for (i in 1:100){
    cat(sprintf("\"%d\" \"%f\"\n",i, cp(i,sortedless)))
  }
  print("Users who processed more than $100")
  print("percentile % cp")
  for (i in 1:100){
    cat(sprintf("\"%d\" \"%f\"\n",i, cp(i,sortedmore)))
  }

  # Plot ECDFs in R
  #par(mfrow=c(1,2))
  #plot(sortedless, ecdfless, type="n")
  #lines(sortedless, ecdfless)
  #plot(sortedmore, ecdfmore, type="n")
  #lines(sortedmore, ecdfmore)
  #plot(ecdf(sortedless))
}