Javascript arrays undefined values

Question

I have some code that produces undefined values in an array making no sense.

here is the code:

gcc_py = 8;
gcc_pyd = 12;
var aci = 360/gcc_pyd;
var parcalar = new Array();
var renkler = new Array();

for(var i = 0;i<gcc_pyd;i++){   
    parcalar.push(aci);
    renkler.push('#000');
}

console.log(parcalar);
console.log(renkler);

console.log(parcalar) outputs this:

[ Object , Object , Object , Object , Object , Object , Object , Object , Object , Object , undefined × 2]

do you have any idea for the undefined values in the array?

It outputs `[30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30]` for me. — sachleen, Jun 21 '12 at 18:10
I put that to the Firefox Web console and it prints `[30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30]` and `["#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000"]`. — kennytm, Jun 21 '12 at 18:11
Also, please change new Array(); to [] it's considered better practice — Benjamin Gruenbaum, Jun 21 '12 at 18:11
What happens when you initialize it with `[]` versus `new Array();`? Using `[]` is safer so I would recommend that. It's possible that `Array` might have been overridden by something else. Are you using any third-party libraries? — Vivin Paliath, Jun 21 '12 at 18:14
yes it is the exact code and i have tried `[]` but nothing is changed how can i check whether the other plugins have been changed the prototype of array — Yunus Eren Güzel, Jun 21 '12 at 18:15
@exculuber: What are the contents of the Objects you're seeing in the console? — gen_Eric, Jun 21 '12 at 18:21
@Rocket Object order: 6 value: 30 valueOf: function () { return this.value; } __proto__: Object — Yunus Eren Güzel, Jun 21 '12 at 18:24
@exculuber You clearly have some more code beyond what is posted here. You should show us the entire code if you need help with it. — Nikhil Dabas, Jun 21 '12 at 19:31

score 2 · Accepted Answer · edited May 23 '17 at 11:56

2

I guess you are changing the arrays afterwards. The console will reflect these changes, e.g. then showing objects instead of numbers and strings. Also, when deleting properties from an array (via delete, see Deleting array elements in JavaScript - delete vs splice), they will still show up as initialised but empty (see What is "undefined x 1" in JavaScript?).

edited May 23 '17 at 11:56

Community

1
1

answered Jun 21 '12 at 18:23

Bergi

630,263
148
957
1,375

yes, after these lines there is a function call in which these arrays are passed. The function changes the array. Thank you for the answer. Do you have further information about this concept may be a documentation, link, etc? – Yunus Eren Güzel Jun 21 '12 at 18:28
1

documentation about what? For [console](http://getfirebug.com/wiki/index.php/Console_API) you'll find http://getfirebug.com/logging or http://patik.com/blog/complete-cross-browser-console-log/ helpful. – Bergi Jun 21 '12 at 18:52

score 0 · Answer 2 · edited Jun 21 '12 at 18:14

0

The output for me shows

[30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30]

["#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000"]

Maybe you've added some .prototype stuff to Array somewhere else in the code?

edited Jun 21 '12 at 18:14

sachleen

30,730
8
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answered Jun 21 '12 at 18:13

demiurg

108
10

I'm using raphael.js and its plugin piechart.js – Yunus Eren Güzel Jun 21 '12 at 18:14

score 0 · Answer 3 · answered Jun 21 '12 at 18:15

When I run the same configuration:

<script>
  var gcc_py = 8;
  var gcc_pyd = 12;
  var aci = 360 / gcc_pyd;
  var parcalar = new Array();
  var renkler = new Array();

  for(var i = 0; i < gcc_pyd; i++){
      parcalar.push(aci);
      renkler.push('#000');
  }

  console.log(parcalar);
  console.log(renkler);
</script>

I get:

[30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30]
["#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000", "#000"]

not sure what you're seeing.

My console outputs it as an array of objects do you have any idea for that? — Yunus Eren Güzel, Jun 21 '12 at 18:18

Javascript arrays undefined values

3 Answers3