Thomas Lehmann wrote:
>> class AutoValueDict(dict):
>> def __makeitem__(self, key):
>> return self.setdefault(key, {})
I think it's bad style to invent your own __whatever__() methods, I'd rather
call them _whatever().
>> def __getitem__(self, key):
>> return self.get(key, self.__makeitem__(key))
>>
>> I would like to have a dictionary which ensures dictionaries as values
>> except when I'm assigning another:
>>
>> dict["abc"]["xyz"]["123"]["456"] = 123
>>
>> How can I do this without many "if" and "else"?
>>
>
> Oh no... of course like this:
> return self.setdefault(key, AutoValueDict())
>
An alternative implementation (requires Python 2.5):
>>> class A(dict):
... def __missing__(self, key):
... print "creating subdict for", key
... value = A()
... self[key] = value
... return value
...
>>> a = A()
>>> a["x"]["y"]["z"] = 42
creating subdict for x
creating subdict for y
>>> a
{'x': {'y': {'z': 42}}}
Peter
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