PEP 584 – Add + and – operators to the built-in dict class

Re:PEP 584 – Add + and – operators to the built-in dict class by kbd on Wednesday March 06, 2019 @02:59PM (#19322180)

> it’s not super obvious what to do when the keys are equal

    d1 | d2 | d3 | ...

is equivalent to:

    {**d1, **d2, **d3, ...}

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Re:PEP 584 – Add + and – operators to the built-in dict class by dan-robertson on Wednesday March 06, 2019 @03:11PM (#19322293)

Now read the above but instead of “it’s not super obvious what

  d1 | d2

should be because losing information/desirable properties/weird errors”, read “it’s not super obvious what

  {**d1, **d2}

should be because losing information/desirable properties/weird errors”.

Except I guess one could throw in something about TOOWTDI too.

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Re:PEP 584 – Add + and – operators to the built-in dict class by kbd on Wednesday March 06, 2019 @03:42PM (#19322542)

I actually think it is obvious what a dictionary merge should do (overwrite keys on the left with keys on the right), but this is besides the point because it's already been determined for

    {**d1, **d2}

In other words, there are no new semantics to discuss here. I'm just saying the two syntaxes should be equivalent.

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