[Python-Dev] Proposal: defaultdict
"Martin v. Löwis"
martin at v.loewis.de
Sat Feb 18 00:06:20 CET 2006
Ian Bicking wrote:
> I know *I* at least don't like code that mixes up access and
> modification. Maybe not everyone does (or maybe not everyone thinks of
> getitem as "access", but that's unlikely). I will assert that it is
> Pythonic to keep access and modification separate, which is why methods
> and attributes are different things, and why assignment is not an
> expression, and why functions with side effects typically return None,
> or have names that are very explicit about the side effect, with names
> containing command verbs like "update" or "set". All of these
> distinguish access from modification.
Do you never write
d[some_key].append(some_value)
This is modification and access, all in a single statement, and all
without assignment operator.
I don't see the setting of the default value as a modification.
The default value has been there, all the time. It only is incarnated
lazily.
Regards,
Martin
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