Thank You so much acer.

I never realize how much the "sort" function can be used.

That is really cool

Thank you acer!

But What I mean is prority of the list. We firstly sort the list of list accoring to the third element, and then the forth.

I mistyped in something.

It is acutally

[[1,2,3,4],[2,3,5,5],[3,4,4,6],[4,5,5,3]];

So then

[[1,2,3,4],[3,4,4,6],[2,3,5,5],[4,5,5,3]]

Here the last two list, since they have the same third element. I want to sort only them ascendtly according to their fourth element.

[[1,2,3,4],[3,4,4,6],[4,5,5,3],[2,3,5,5]]

That is all I want to do.

But your answer is really good and gives me a new method of sorting list.