[Python-Dev] Proposal: defaultdict (original) (raw)

Delaney, Timothy (Tim) tdelaney at avaya.com
Thu Feb 16 22:27:04 CET 2006

Guido van Rossum wrote:

Over lunch with Alex Martelli, he proposed that a subclass of dict with this behavior (but implemented in C) would be a good addition to the language. It looks like it wouldn't be hard to implement. It could be a builtin named defaultdict. The first, required, argument to the constructor should be the default value. Remaining arguments (even keyword args) are passed unchanged to the dict constructor.

Feedback?

On behalf of everyone who has answered this question on c.l.py, may I say WOOHOO!

FWIW, my usual spelling is:

try:
    v = d[key]
except:
    v = d[key] = value

which breaks the principle of "write it once".

Tim Delaney

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