[Stefan Pochmann <smpochm...@gmail.com>]
> It crashes because it tries to convert 10**400 to a float and that fails:
>
> >>> 10**400 / 1e200
> Traceback (most recent call last):
> File "<pyshell#10>", line 1, in <module>
> 10**400 / 1e200
> OverflowError: int too large to convert to float
>
> But with two ints it succeeds:
>
> >>> 10**400 / 10**200
> 1e+200
Simlalary for 1e200 / 10**400. That is, it doesn't matter to this
whether int.__truediv__ or float.__truediv__ is invoked. If the types
are mixed, the operands are coerced to float first.
> Note that 1e200 is an integer:
>
> >>> 1e200.is_integer()
> True
>
> So that could losslessly be converted to int, and then the division would
> succeed:
>
> >>> 10**400 / int(1e200)
> 1e+200
>
> So could/should 10**400 / 1e200 be implemented to do that instead of
> raising the error?
It could. But I don't think it "should".
> Or is it a too rare use case and not worth the effort, or does
> something else speak against it?
Too rare, and expensive. int.__truediv__ makes semi-heroic efforts to
get 10**400 / int(1e200) "right" (well, as right as can be), and
that's expensive, and probably more surprising than not.for most
users. For example,
>>> int(1e200)
99999999999999996973312221251036165947450327545502362648241750950346848435554075534196338404706251868027512415973882408182135734368278484639385041047239877871023591066789981811181813306167128854888448
is, all on its own, probably more surprising than not for most users.
It's not to me (or presumably to you), but I have no use for Python
magically converting a float to int. It doesn't in other contexts
either:
[1, 2, 3][2.0]
Traceback (most recent call last):
...
TypeError: list indices must be integers or slices, not float
In purely computational contexts, "when an inf and a float are mixed,
the int is converted to a float first" is a simple, predictable,and
reliable rule:
>>> pow(10**400, 0.5)
Traceback (most recent call last):
,,,
OverflowError: int too large to convert to float
In practice, over decades I've seen that kind of exception only a
handful of times, and it always pointed to a logical error in my code.
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