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Comment by fulafel | Hacker News Reader

The problem with sprinkling operator overloading all over the place in non numerical use is that you as tje reader don't get the context hints provided by method names. I think this change is bad in the overall balance.

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The best way to do dictionary union is already symbolic:

    {**d1, **d2}

This provides a clearer symbolic notation for dictionaries analogous to what's already available with sets. FWIW the pep discusses what this would look like as a method vs an operator:

https://www.python.org/dev/peps/pep-0584/#use-a-method

The best way for in my view is .union(), the new syntax additions are too cryptic.

I agree. Back in the day when I used Ruby, I remember one of the arguments for Python being their belief that there should be one way to do things. Found one reference:

> There should be one-- and preferably only one --obvious way to do it.

https://www.python.org/dev/peps/pep-0020/

There should be one _obvious_ way to do things. Not _one_ way to do things.

The operator is better than the dict unpacking-repacking trick, and will become the obvious way to do it.

we already have `set1 | set2` for set unions

and dict keys are basically a set

I think that's cryptic too for most people, intuitive just for people who are conversant in bitwise operations.

these are standard set operations, not bitwise

The choice of the "|" operator for set union comes from bitwise operations: bitwise OR works as a union operator if you are using integers as bit vectors to represent sets of boolean attributes. And it was a common idiom back in the day when people used to program in C/assembly, using words as bit vectors was a common way to save memory.

Hence "|" as set union is intuitive for people who are familiar with this application of bit vectors.

I think the OR operator comes from set theory and has nothing to do with the low-level boolean flag fieldsets.

I looked up set theory a couple of places (WP[1] and Britannica[2]) and didn't find any references of the OR operator in this context.. do you have a link?

[1] https://en.wikipedia.org/wiki/Algebra_of_sets

[2] https://www.britannica.com/science/set-theory/Operations-on-...

The analogue of the OR operator in set theory is the union operator. People think of them as basically the same thing because of the correspondence between a property and the set of things with that property. If A is the property of being either B or C, then the set of the things that are A is the union of the set of things that are B and the set of things that are C.

Not sure what you're referring to because there is no "union" method/function. There is currently no non-symbolic built-in way to combine dictionaries in an expression.

You may be interested to read PEP 584's list of examples of all the real-world code the existence of this operator makes clearer:

https://www.python.org/dev/peps/pep-0584/#examples

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