[Python-Dev] Deprecating float.is_integer()

[Robert Smallshire]

In the PR which implements is_integer() for int, the numeric tower, and
Decimal I elected not to implement it for Complex or complex. This was
principally because complex instances, even if they have an integral real
value, are not convertible to int and it seems reasonable to me that any
number for which is_integer() returns True should be convertible to int
successfully, and without loss of information.

  >>> int(complex(2, 0))

  Traceback (most recent call last):

    File "<stdin>", line 1, in <module>

  TypeError: can't convert complex to int


There could be an argument that a putative complex.is_integral() should
therefore return False, but I expect that would get even less support than
the other suggestions in these threads.

*Robert Smallshire | *Managing Director
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On 22 March 2018 at 10:51, Kirill Balunov <kirillbalunov at gmail.com> wrote:

> I apologize that I get into the discussion. Obviously in some situations
> it will be useful to check that a floating-point number is integral, but
> from the examples given it is clear that they are very rare. Why the
> variant with the inclusion of this functionality into the math module was
> not considered at all. If the answer is - consistency upon the numeric
> tower - will it go for complex type and what will it mean (there can be two
> point of views)?
>
> Is this functionality so often used and practical to be a method of float,
> int, ..., and not just to be an auxiliary function?
>
> p.s.: The same thoughts about `as_integer_ratio` discussion.
>
> With kind regards,
> -gdg
>
>
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