Find the Median of an Array

Finding the median of an unsorted array

You can use the Median of Medians algorithm to find median of an unsorted array in linear time.

How to calculate the median of an array?

The Arrays class in Java has a static sort function, which you can invoke with Arrays.sort(numArray).

Arrays.sort(numArray);
double median;
if (numArray.length % 2 == 0)
    median = ((double)numArray[numArray.length/2] + (double)numArray[numArray.length/2 - 1])/2;
else
    median = (double) numArray[numArray.length/2];

Find the median in my array while also sorting the numbers from smallest to largest

Median is the middle element of the sorted array if the array size is odd, else it is the average of the middle two elements. The following code snippet finds the median of the array.

public static void main(String[] args) {
        int[]num = {60, 70, 82, 1216, 57, 82, 34, 560, 91, 86};
        int median;
        int len = num.length;
        
        Arrays.sort(num); // sorts the array
        
        //check if the length is odd
        if(len%2 != 0)
            median = num[len/2];
        else // length is even
            median = (num[(len - 1) / 2] + num[len / 2])/2;
        System.out.println(median);
    }

Find the median of an array

I'm going to just jump in with a solution here...

def median(ary)
  mid = ary.length / 2
  sorted = ary.sort
  ary.length.odd? ? sorted[mid] : 0.5 * (sorted[mid] + sorted[mid - 1])
end

Edit - I've incorporated .odd? as per BroiSatse's suggestion.

Calculating median - javascript

Change your median method to this:

function median(values){
  if(values.length ===0) throw new Error("No inputs");

  values.sort(function(a,b){
    return a-b;
  });

  var half = Math.floor(values.length / 2);
  
  if (values.length % 2)
    return values[half];
  
  return (values[half - 1] + values[half]) / 2.0;
}

fiddle

Get median of array

To get the median you can use the following:

let median = arr.sorted(by: <)[arr.count / 2]

In your case it will return 5.

As @Nirav pointed out [1,2,3,4,5,6,7,8] will return 5 but should return 4.5.

Use this instead:

func calculateMedian(array: [Int]) -> Float {
    let sorted = array.sorted()
    if sorted.count % 2 == 0 {
        return Float((sorted[(sorted.count / 2)] + sorted[(sorted.count / 2) - 1])) / 2
    } else {
        return Float(sorted[(sorted.count - 1) / 2])
    }
}

Usage:

let array = [1,2,3,4,5,6,7,8]
let m2 = calculateMedian(array: array) // 4.5

Median of an array in Javascript?

var ar1 = [];
while (true) {  var enterValues = prompt("enter your values");  if (enterValues != "") {    ar1.push(parseFloat(enterValues));  } else {    break;  }}
function calcMedian() {  var half = Math.floor(ar1.length / 2);    ar1.sort(function(a, b) { return a - b;});    if (ar1.length % 2) {    return ar1[half];  } else {    return (ar1[half-1] + ar1[half]) / 2.0;  }}
console.log(ar1);console.log(ar1.length);console.log(calcMedian());console.log(ar1);