"binom.exact" <-
  function(x, n, conf.level = .95) {
  # x = number of successes
  # n = number of trials
  # do calculations
  xnc <- cbind(x,n,conf.level)
  lower <- numeric(nrow(xnc))
  upper <- numeric(nrow(xnc))
  for(i in 1:nrow(xnc)){
    ci <- binom.test(x=xnc[i,1], n=xnc[i,2], conf.level=xnc[i,3])$conf.int
    lower[i] <- ci[1]
    upper[i] <- ci[2]
  }
  # collect results into one object
  cbind(x = x, n = n, proportion = x/n, conf.level = conf.level, lci = lower, uci = upper)
}