Has Next in Python Iterators

[Paul Rudin]

Kelson Zawack <zawackkfb at gis.a-star.edu.sg> writes:

> The example I have in mind is list like [2,2,2,2,2,2,1,3,3,3,3] where
> you want to loop until you see not a 2 and then you want to loop until
> you see not a 3.

"loop until you see not a 2" - you mean yield 2s as long as there are 2s
to be consumed?

"loop until you see not a 3" - you mean yield 3s as long as there are 3s
to be consumed?

So in this case you'd see just the initial 2s? (Since the 1 immediately
follows the 2s and is "not a 3")

def twos_then_threes(iterable):
    i = iter(iterable)
    n = i.next()
    while n==2:
       yield n
       n=i.next()
    while n==3:
       yield n
       n=i.next()

so... no need for any has_next()

or do I misunderstand what you want to do? Probably this can be done
with some itertools.groupby() cunningness...