What does "::" mean?

[Robert Kern]

could ildg wrote:
> 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?

The full form would be live[len(live)-1:-1:-1] much like 
range(len(live)-1, -1, -1).

[start:stop:step]
step can be negative.

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
  Are the graves of dreams allowed to die."
   -- Richard Harter