R median function from scratch

Question

I am a R beginner and I tried to make a median function from scratch.

Here is my code:

mymedian <- function(x) {
  len <- length(x)
  sorted <- sort(x)
  if (len %% 2 == 0) {
    med1 <- sorted[len / 2]
    med2 <- sorted[(len + 1) %/% 2]
    result <- sorted[med1 + med2 / 2]
    return(result)
  } else {
    result <- sorted[(len + 1)/2]
    return(result)
  }
}

Im getting "NA" output. I couldn't find where the problem is.

Answer 1

Main issue is you're trying to index your sorted vector with a non-integer (e.g., 168.5). Compare your function to this:

mymedian <- function(x){
  len <- length(x)
  sorted <-sort(x)
  if(len%%2==0){
    i <- len/2
    med1<-sorted[i]
    med2 <- sorted[i+1]
    result <- sum(med1,med2)/2
    return(result)
  }else{
    result<-sorted[(len+1)/2]
    return(result)
  }
}