[Python-Dev] Counter proposal: multidict (was: Proposal: defaultdict) (original) (raw)

Jack Diederich jack at performancedrivers.com
Fri Feb 17 21:25:14 CET 2006

On Fri, Feb 17, 2006 at 03:03:06PM -0500, Fred L. Drake, Jr. wrote:

On Friday 17 February 2006 14:51, Ian Bicking wrote: > and in the process breaking an important > quality of good Python code, that attribute and getitem access not have > noticeable side effects.

I'm not sure that's quite as well-defined or agreed upon as you do.

Without the getitem side effect default objects that don't support any operators would have problems.

d[key] += val

works fine when the default is a list or int but fails for dicts and presumably many user defined objects. By assigning the default value in getitem the returned value can be manipulated via its methods.

-Jack

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