Ellipsis usage?

[Christophe Delord]

On Wed, 18 Feb 2004 11:39:04 -0500, Wayne Folta wrote:

> I see Ellipsis documented under slicing, though it appears it's not 
> used in slicing but rather slicing-like notation for dictionary keys. 
> It's a minor thing but none of the books I have even mention it. Is it
> 
> obsolete in python 2.x or still useful?
> 
> 

Hello,

I have used Ellipsis in a project where the ... notation was more
adapted than : (because x:y had another meaning in our context).

I had a class similar to this one:

class MyRange:

    def __init__(self, lst):
        self.lst = lst

    def __getitem__(self, slice):
        r = []
        items = list(slice)
        while items:
            a = items.pop(0)
            if items[:1] == [Ellipsis]:
                items.pop(0)
                b = items.pop(0)
                r.extend(self.lst[a:b+1])
            else:
                r.append(self.lst[a])
        return r

r = MyRange(list("abcdefghijklmnopqrstuvwxyz"))
print r[1, 2, 3, 10, ..., 15]

should print ['b', 'c', 'd', 'k', 'l', 'm', 'n', 'o', 'p']


But I don't know exactly what's the real use of Ellipsis and if it will
exist in the future.