What does "::" mean?

[Paul Villani]

I'm very new to Python, but....

I think it's really ':' and ':' side-by-side with no values, not a single 
"::".

In V2.3 and higher, slicing supports an optional third index which works as 
a step, e.g.,

X[2:9:2]

fetches every other item in indexes 2-8.  The useage you cite is really 
defaulting the start and end indexes, and decrementing the step index.

Regards,

"could ildg" <could.net at gmail.com> wrote in message 
news:mailman.1932.1121820680.10512.python-list at python.org...
I know that ":" can do slice works.
But I saw "::" today and it puzzled me much,
I can't find it in the python doc,
so I raise this question here.
The code is as below:
----------------------------------------------------------
Jython 2.2a1 on java1.5.0_03 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>> live='live';print live
live
>>> live=live[::-1];print live
evil
>>>
--------------------------------------------------------
"[::-1]" can reverse a string magicly, how did it do it?