jQuery: Assign class based on index

Question

Using jQuery, is it possible to assign a class to an object based on its index?

For example, if I have an ul with five list items, how would I assign the class "0" to the first item, "1" to the second item, "2" to the third, item and so on?

This was my first attempt:

$('ul.nav li').each(function(index){
  $(this).addClass(index);
});

Answer 1

But avoid to start class or id with number;

$('ul.nav li').each(function(index){
  $(this).addClass('at_'+ index);
});

Answer 2

Bearing in mind that classes can't start with numbers, something like this should do:

$('ul.nav li').each(function(){
  $(this).addClass("index_"+$(this).index);
});

Answer 3

Class names should not start with numbers. Instead do something like

$('ul.nav li').each(function(index){
  $(this).addClass("class_"+index);
});

Answer 4

It is working for me with this:

$('ul.nav li').each(function(index){
  $(this).attr('class', 'class'+index);
});​

http://jsfiddle.net/8JCXD/7/