Sorting array of float point numbers [duplicate]

Question

I have an array of float point numbers:

[ 82.11742562118049, 28.86823689842918, 49.61295450928224, 5.861613903793295 ] 

After running sort() on the array I get this:

[ 28.86823689842918, 49.61295450928224, 5.861613903793295, 82.11742562118049 ] 

Notice how 5.8... is bigger than 49.6... for JavaScript (Node). Why is that?

How can I correctly sort this numbers?

Answer 1

Pass in a sort function:

[….].sort(function(a,b) { return a - b;}); 

results:

[5.861613903793295, 28.86823689842918, 49.61295450928224, 82.11742562118049]  

From MDN:

If compareFunction is not supplied, elements are sorted by converting them to strings and comparing strings in lexicographic ("dictionary" or "telephone book," not numerical) order.

Answer 2

The built in JS sort function treats everything as strings. Try making your own:

var numbers = new Array ( 82.11742562118049, 28.86823689842918, 49.61295450928224, 5.861613903793295 );  function sortFloat(a,b) { return a - b; }  numbers.sort(sortFloat);