Multidimensional Dictionaries: Possible?

[bjorn]

> What's the quickest way to do the equivalent of the following Perl in Python,
> again, using the above example:
>
> $dict{$key1}{$key2}++
>
> I can only think of the following, I hope there is a better way! :
>
> a =  dict[key1, key2]
> a = a + 1
> dict[key1, key2] = a

How about:

class Counter:
    def __init__(self, n):
        self.n = n

    def inc(self):
        self.n = self.n + 1
        return self.n

dict[key1, key2] = Counter(0)
dict[key1, key2].inc()

-- bjorn