CODEWITHSUNDEEP
javascriptjquery
finspin
finspin

Reputation: 4061

Issue with sorting an array

I'm learning javascript and can't figure out the problem in my code below. I guess I misunderstand how arrays actually work.

The problem is that the alerted array is not actually sorted. I would be grateful for any insights on this:

Here is a ready jsFiddle.

HTML:

<html>
  <head>
    <title>
      Test 1
    </title>
    <script src="http://code.jquery.com/jquery-latest.js" type=
    "text/javascript">
</script>
  </head>
  <body>
    <div class="items">
      <ul>
        <li>
          <a href="#" id="1">Link 1</a>
        </li>
        <li>
          <a href="#" id="2">Link 2</a>
        </li>
        <li>
          <a href="#" id="3">Link 3</a>
        </li>
        <li>
          <a href="#" id="4">Link 4</a>
        </li>
      </ul>
    </div>
</body>
</html>

Javascript:

var clickedLinks = [];
var passedItems = [];


// Collect clicked link IDs into an array and pass the array as an argument to shoplist()
$('.items a').click(function () {

if (clickedLinks.indexOf(this.id) != -1) {
    var linkIndex = clickedLinks.indexOf(this.id);
    clickedLinks.splice(linkIndex, 1);
} else {
    clickedLinks.push(this.id);
}

shoplist(clickedLinks);

});


function shoplist(ids) {
    passedItems.push(ids.slice());
    alert(passedItems.sort());
}

Steps to reproduce:

  1. Click Link 2
  2. Click Link 1

Expected Result: 1, 2, 2

Actual Result: 2, 2, 1

Things I've tried:

function shoplist(ids) {
    passedItems.push(ids.slice());
    var newpi = passedItems.slice();
    alert(newpi.sort());
    }

Upvotes: 1

Views: 90

Answers (3)

Jo&#227;o Silva
Jo&#227;o Silva

Reputation: 91309

You are adding an array, the result of ids.slice(), to another array. That's why the sort doesn't work as you expect. Use concat instead, if you want to add the contents of ids to the passedItems array:

passedItems = passedItems.concat(ids);

Also, instead of adding a string to the ids array, you should use .push(parseInt(this.id)) instead, and then use:

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

Upvotes: 1

PitaJ
PitaJ

Reputation: 15012

I hope this will work:

http://jsfiddle.net/DZpDG/4/

Upvotes: 0

aug
aug

Reputation: 11714

I think you're using the sort function wrong. If you want to use the sort function numerically, you have to include a sort function. If you want to sort things numerically you should use this function (provided in the link):

(function(a,b){return a-b});

So in your scenario for the newpi it would look like this:

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

Upvotes: 2

Related Questions