Grouping lists

[PyPK]

hmm thanks for that..but kind of not sure how this groupby works.. also
if I want to group elements with one value apart how would this
change.Should this change in groupby part or in the loop?
something like...
lst = [1,1,2,1,3,5,1,1,1,1,2,7,7]
returns (0,3),4,5,(6,10),(11,12)
so its something like if there is 1,1,2 then the grouping is done..
I am asking this as I could not quit follow what exactly groupby does..

Also if someone could explain me what exactly this groupby is doing
that would be helpful.

Thanks again.