Is it possible to access current object while doing list/dict comprehension in Python?

Question

Trying to think of a one-liner to achieve the following ( summing all the values of a key) :

>>> data = [(\'a\',1),(\'b\',3),(\'a\',4),(\'c\',9),(\'         


        

Answer 1

Use reduce and collections.Counter:

>>> from operator import add
>>> from collections import Counter
>>> reduce(add, (Counter(dict([x])) for x in data))
Counter({'c': 9, 'a': 5, 'b': 4, 'd': 3})