Python: determine length of sequence of equal items in list

Question

I have a list as follows:

l = [0,0,0,0,0,0,1,1,1,1,1,1,0,0,0,0,2,2,2]

I want to determine the length of a sequence of equal items, i.e for

Answer 1

Mike's answer is good, but the itertools._grouper returned by groupby will never have a __len__ method so there is no point testing for it

I use sum(1 for _ in i) to get the length of the itertools._grouper

>>> import itertools as it
>>> L = [0,0,0,0,0,0,1,1,1,1,1,1,0,0,0,0,2,2,2]
>>> [(k, sum(1 for _ in i)) for k, i in it.groupby(L)]
[(0, 6), (1, 6), (0, 4), (2, 3)]