[Python-Dev] dict.addlist()

Moore, Paul Paul.Moore at atosorigin.com
Tue Jan 20 09:41:19 EST 2004

From: Raymond Hettinger
> [Bob Ippolito]
>> d.setdefault(k, factory=list).append(v) ?
> That is somewhat nice and backwards compatible too.


How is it more expressive than d.setdefault(k, []).append(v)? As
far as I can see, it's longer and contains an extra obscure(ish)
term (factory).

And I agree with the other posters that other defaults are often
useful, and further complicating the dictionary interface isn't
particularly helpful.

If conciseness is important,

    def addlist(d, k, v):
        d.setdefault(k, []).append(v)


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