javascriptarrayssortingnumbers

How to sort an array of integers?

Trying to get the highest and lowest value from an array that I know will contain only integers seems to be harder than I thought.

var numArray = [140000, 104, 99];
numArray = numArray.sort();
console.log(numArray)

I'd expect this to show 99, 104, 140000. Instead it shows 104, 140000, 99. So it seems the sort is handling the values as strings.

Is there a way to get the sort function to sort on the integer value of each array element?

Solution

  • By default, the sort method sorts elements alphabetically. To sort numerically just add a new method which handles numeric sorts (sortNumber, shown below) -

    var numArray = [140000, 104, 99];
numArray.sort(function(a, b) {
  return a - b;
});

console.log(numArray);

    Documentation:

    Mozilla Array.prototype.sort() recommends this compare function for arrays that don't contain Infinity or NaN. (Because Infinity - Infinity is NaN, not 0).

    Also examples of sorting objects by key.