Re: Adding "+" and "+=" operators to dict
[Posted March 4, 2015 by jake]
| From: |
| Greg <greg.ewing-F+z8Qja7x9Xokq/tPzqvJg-AT-public.gmane.org> |
| To: |
| python-ideas-+ZN9ApsXKcEdnm+yROfE0A-AT-public.gmane.org |
| Subject: |
| Re: Adding "+" and "+=" operators to dict |
| Date: |
| Thu, 12 Feb 2015 17:06:33 +1300 |
| Message-ID: |
| <54DC26C9.4060801@canterbury.ac.nz> |
On 12/02/2015 4:59 p.m., Chris Angelico wrote:
>> Addition in the usual sense of the word wouldn't be commutative for
>> dictionaries.
>
> Does it have to be? It isn't commutative for strings or tuples either.
I think associativity is the property in question, and it
does hold for string and tuple concatenation.
Dict addition could be made associative by raising an
exception on duplicate keys.
Another way would be to define {'a':x} + {'a':y} as
{'a': x + y}, but that would probably upset a lot of
people. :-)
--
Greg
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