List - rotate

[ameoba]

"Alex Martelli" <aleax at aleax.it> wrote in news:a2mf02$86k$1 at serv1.iunet.it:

> s[1:]+s[0:1] yields a "rotated copy" for ANY sequence s, be it
> a string, a list, a tuple, whatever.  But you need to
> assign it to something, else it will go away as soon
> as you're done with it.  It does NOT modify s in-place
> in any case (strings and tuples are mutable, lists are
> mutable but no mutation is performed in this case).


Of course, this is easily abstractable to rotating a list by any arbitrary 
ammount...  But it got me to wondering;  is there a good way to add a 
method to strings?

Not so much to make a class derived from the string type, but just to add a 
function to it.

If it can't be done with a built-in class like string, can methods be added 
to user-defined classes outside of the original class definition without 
subclassing them?

Not so much that I want to do this, just that I'm curious as to how dynamic 
of an environment Python really is.