Sorting of an array in JavaScript

Question

arr=[-37.507,-3.263,40.079,27.999,65.213,-55.552];
arr.sort();

and the result is

arr=[-3.263,-37.507,-55.552,27.999,40.079,65.213]

Can any one help me what logic that "sort()" function is doing? Please explain me why "arr.sort();" gives the above result.? And other questions doesn't have the exact answer which explains what i am getting here.

You can have a look here http://stackoverflow.com/questions/234683/javascript-array-sort-implementation — Raj Kumar, Nov 26 '14 at 07:33
@RajKumar Thank you, But by using this function i couldn't able to get correct sorted array, U could see that in my question . Please explain it. — Prabhu Vignesh Rajagopal, Nov 26 '14 at 07:39
re: "other questions doesn't have the exact answer"; yes they do. The [accepted answer](http://stackoverflow.com/a/1063027/660921) on this question says: "By default the sort method sorts elements alphabetically"; which is exactly the problem you have, and the description is exactly the same as the answer you accepted on this question. — Martin Tournoij, Nov 27 '14 at 20:33

score 3 · Accepted Answer · answered Nov 26 '14 at 07:30

3

array.sort sorts strings, if you want to sort numerically, you need a comparison-function:

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

answered Nov 26 '14 at 07:30

MBaas

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Thank you @MBaas, But you can see that the result is wrong which is in my question could you explain it please? – Prabhu Vignesh Rajagopal Nov 26 '14 at 07:37
The results is correct, pls. check here: http://jsfiddle.net/evpt2wfr/ – MBaas Nov 26 '14 at 07:41

score 0 · Answer 2 · answered Nov 26 '14 at 07:30

The default sort function treats each item as a string. Lexicographic order is not the same as numerical order. For numerical sorting, do this:

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

The argument to sort() is a function that returns a negative number only if a comes before b.

score 0 · Answer 3 · answered Nov 26 '14 at 07:31

0

use this:

arr.sort(function(a, b) {
    if (a>b) return 1;
    if (a<b) return -1;
    if (a==b) return 0;
});

answered Nov 26 '14 at 07:31

sadrzadehsina

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Sorting of an array in JavaScript

3 Answers3