intersection, union, difference, symmetric difference for dictionaries
Peter Otten
__peter__ at web.de
Tue Feb 25 15:53:18 EST 2014
mauro wrote:
> Dictionaries and sets share a few properties:
> - Dictionaries keys are unique as well as sets items
> - Dictionaries and sets are both unordered
> - Dictionaries and sets are both accessed by key
but sets have no values
> - Dictionaries and sets are both mutables
but frozensets also have the operations mentioned in the subject.
> So I wonder why operations such us intersection, union, difference,
> symmetric difference that are available for sets and are not available
> for dictionaries without going via key dictviews.
How would you define them?
E. g.
{1, 2} & {2, 3} == {2}
but
{1:"a", 2:"b", 3:"c"} & {2:"b", 3:"e", 4:"f"} == ???
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?
More information about the Python-list
mailing list