Dictionary union (PEP 584) is merged

Re:Dictionary union (PEP 584) is merged by seemslegit on Tuesday February 25, 2020 @05:53PM (#22418405)

imo

  defaultdict(callback,{**a,**b})

is more readable than a | b without knowing that a or b are defaultdicts and having to reason about which default callback will be used

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Re:Dictionary union (PEP 584) is merged by orf on Wednesday February 26, 2020 @03:31AM (#22421393)

It’s also really expensive. This new operator works with any Mapping type without needing silly hacks.

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Re:Dictionary union (PEP 584) is merged by anonymoushn on Tuesday February 25, 2020 @10:19PM (#22419983)

Note that a | b is already a disaster if you try to use subclasses of set. In python 2.7, iirc it would return a set of a's type but without calling the constructor. In python 3 it seems to return a set (not the type of a or the type of b).

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Re:Dictionary union (PEP 584) is merged by CameronNemo on Tuesday February 25, 2020 @11:29PM (#22420280)

Not sure about the set operator, but this operator is meant to handle subclasses better than the status quo.

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Re:Dictionary union (PEP 584) is merged by mdrachuk on Wednesday February 26, 2020 @12:55AM (#22420664)

Wow, one more point for python 3.

Just override ‘__and__’ in your whatever class to replace default return.

Pretty explicit in my book.

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