07.10.20 06:04, Guido van Rossum пише:
> Ironically, complex numbers have a `__float__`
> method that always fails, and floats don't have a `__complex__` method
> but complex(x) succeeds if x is a float...
I wonder why not remove complex.__float__ (and complex.__int__,
complex.__floordiv__, etc)?
I wonder the same thing myself and I bet it gets complicated fast.
I was trying to use the numbers module to type hint any number including both floats and decimal.Decimal the other evening. It doesn't work... type checkers don't know Decimal is a Number. Finally I discovered the correct current solution is just Union[Decimal, float] or Union[Decimal, float, Real] if you want to include other real numbers like fractions.Fraction.
St first I was really annoyed but from what I was able to gather after some reading Monday evening, this is a known problem that is getting worked on and is because the abcs in the current numbers module are somewhat unusable for type hinting and need to be replaced/updated to make Number and friends into protocols. And I came away grateful there are smart people people working on this to make things better, rather than annoyed. I'll be interested to see what is come up with as a solution in 3.10.