[jQuery] Change opacity of item with class of selected

[Paul Collins]

Hi all

I've been stuck on this for four hours, and I still can't solve it!

I am trying to check if a list item has a class of selected, then is so
change the opacity to 0.5. Here is my code:

    if ($("#portfolio #thumbs ul li").hasClass(".selected")) {
        $(this).css('opacity','0.5');
    }

It seems that the "this" part isn't working, is it to do with putting it in
an event?

Would appreciate any help