intersection, union, difference, symmetric difference for dictionaries

Tue Feb 25 17:35:00 EST 2014

On 25/02/2014 22:11, mauro wrote:
>>>>> {1, 2} & {2, 3} == {2}
>>> In my mind the intersection is evaluated on keys, so the resulting dict
> should be the empty one
>> but
>>>> {1:"a", 2:"b", 3:"c"} & {2:"b", 3:"e", 4:"f"} == ???
> my output will be
> {2:"b", 3:"e"}
> or
> {2:"b", 3:"c"}
>> depending on the implementation choice.
>>>> The most obvious result is probably the empty dict {2:"b"}, i. e.
>>>> a & b is defined as dict(a.items() & b.items())
>>>> Frankly, I don't do that a lot. So what's your use-case?
> I do not have an use case, but I've seen that many people ask for these
> operations for example in stackoverflow.com
>
Please ask one of the many people on stackoverflow to raise an 
enhancement request here bugs.python.org complete with a patch that 
changes code, docs and tests and then everybody will be happy, won't they.
-- 
My fellow Pythonistas, ask not what our language can do for you, ask 
what you can do for our language.
Mark Lawrence
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