Approximate any decimal with a rational fraction

rationalFractionApproximator.R

rationalFractionApproximator <- function(dec, maxDenom = 1000){
  denomSeq <- 1:maxDenom
  impliedNumerator <- dec * denomSeq
  roundNumerator <- round(impliedNumerator)
  absError <- abs(roundNumerator / denomSeq - dec)
  minMinimand <- which.min(absError * denomSeq)
  minDenom <- denomSeq[minMinimand]
  minNumer <- roundNumerator[minMinimand]
  
  line2 <- paste0(minNumer, " / ", minDenom, " = ", minNumer / minDenom)
  tempLen <- nchar(paste0(minNumer, " / ", minDenom, " = "))
  line1 <- paste0("match:", paste0(rep(" ", tempLen-6), collapse = ""), dec)
  print(line1)
  print(line2)
  
  out <- list()
  out$Numer <- minNumer
  out$Denom <- minDenom
  return(out)
}