[Python-ideas] PEP: Dict addition and subtraction
python at mrabarnett.plus.com
Fri Mar 8 14:19:17 EST 2019
On 2019-03-08 16:55, Guido van Rossum wrote:
> If we were to use "|" and "&" for dict "union" and "intersection", the
> mutual distributive properties will hold.
> Since "|" (especially "|=") *is* suitable for "update", I think we
> should reserve "+" for some future commutative extension.
> One argument is that sets have an update() method aliased to "|=", so
> this makes it more reasonable to do the same for dicts, which also have
> a. update() method, with similar behavior (not surprising, since sets
> were modeled after dicts).
One way to think of it is that a dict is like a set, except that each of
its members has an additional associated value.
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