How to select li from ul having only one class in jquery

Question

I want to select all li elements from ul having class "one" only

<ul class="one">
<li class="heading">
<li class="list">
<li class="list">
<li class="list">
<li class="list">
</ul>       
<ul class="one two ">
<li class="heading">
<li class="list">
<li class="list">
<li class="list">
<li class="list">
</ul>                        

Answer 1

Easiest:

$('ul[class="one"] li');

Alternative, select .one but not .two:

$('ul.one:not(.two) li');

Answer 2

You can use the jquery filter function to get a count of how many classes have been assigned to the element. When looking for all UL's with class 'one' only then the number of unique classes against the item will be 1. Once you have the filtered UL's you can simply select the sub LI's.

var listItems = 
$('ul.one')
.filter(function(index) {
  return $(this).attr('class').split(' ').length == 1;
})
.find('li');