Understanding slice notation?

Question

I need a good explanation (references are a plus) on Python's slice notation. To me, this notation needs a bit of picking up. It looks extremely powerful, but I haven't quite got my head around it.

Answer 1

[start,finish,step]

Remember that indexing starts at 0 and the slice will stop one integer before the finish portion. The step part is optional.

a=[1,2,3,4,5,6,7,8]

a[2:5] will give you [3,4,5]

a[2:8:2] will give you [3,5,7]

a[::-1] will give you [8,7,6,5,4,3,2,1]