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[Python-ideas] Adding "+" and "+=" operators to dict

Donald Stufft donald at stufft.io
Fri Feb 13 00:47:13 CET 2015 
> On Feb 12, 2015, at 6:43 PM, Eric Snow <ericsnowcurrently at gmail.com> wrote:
> 
> On Thu, Feb 12, 2015 at 3:43 AM, Steven D'Aprano <steve at pearwood.info> wrote:
>> A very strong -1 on the proposal. We already have a perfectly good way
>> to spell dict += , namely dict.update. As for dict + on its own, we have
>> a way to spell that too: exactly as you write above.
> 
> From what I understand, the whole point of "d + d" (or "d | d") is as
> an alternative to the PEP 448 proposal of allowing multiple keyword
> arg unpacking clauses ("**") in function calls.  So instead of "f(**a,
> **b)" it would be "f(**a+b)" (or "f(**a|b)").  However, the upside to
> the PEP 448 syntax is that merging could be done without requiring an
> additional intermediate dict.  Personally, I'd rather have the syntax
> than the operator (particularly since it would apply to the dict
> constructor as well: "dict(**a, **b, **c)”)

That’s one potential use case but it can be used in a lot more situations
than just that one. Hence why I said in that thread that being able to
merge dictionaries is a much more general construct than only being able
to merge dictionaries inside of a function call.

---
Donald Stufft
PGP: 7C6B 7C5D 5E2B 6356 A926 F04F 6E3C BCE9 3372 DCFA

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