Concise idiom to initialize dictionaries

[Peter Otten]

Frohnhofer, James wrote:

> My initial problem was to initialize a bunch of dictionaries at the start
> of a function.
> 
> I did not want to do
> def fn():
> a = {}
> b = {}
> c = {}
> . . .
> z = {}
> simply because it was ugly and wasted screen space.

Here is a bunch of dictionaries that spring into existence by what is
believed to be magic :-)

>>> class AllDicts:
...     def __getattr__(self, name):
...             d = {}
...             setattr(self, name, d)
...             return d
...     def __repr__(self):
...             items = self.__dict__.items()
...             items.sort()
...             return "\n".join(map("%s -> %r".__mod__, items))
...
>>> ad = AllDicts()
>>> ad.a[1] = 99
>>> ad.b[2] = 42
>>> ad.b[3] = 11
>>> ad
a -> {1: 99}
b -> {2: 42, 3: 11}

Peter