On 10/14/2019 12:54 AM, Andrew Barnert via Python-ideas wrote:
On Oct 13, 2019, at 22:54, Chris Angelico wrote:
Mathematically, what's the difference between '1' and '1+0j' (or
'1+0i')?
Again, think of Python, but don’t take the analogy too far. You can use `1`
almost anywhere you can
Andrew Barnert via Python-ideas writes:
> People often think “well, natural numbers aren’t closed over
> subtraction, so we’ll just always use integers, and integers aren’t
> closed over division so we’ll just always use rationals, …”
> assuming that if you keep following that you get to the
On Oct 14, 2019, at 06:07, Steven D'Aprano wrote:
>
>> On Mon, Oct 14, 2019 at 12:54:13AM -0700, Andrew Barnert via Python-ideas
>> wrote:
>>> On Oct 13, 2019, at 22:54, Chris Angelico wrote:
>>>
>>> Mathematically, what's the difference between '1' and '1+0j' (or
>>> '1+0i')?
>>
>> The
On 14/10/2019 18:25, Andrew Barnert via Python-ideas wrote:
On Oct 14, 2019, at 01:53, Chris Angelico wrote:
On Mon, Oct 14, 2019 at 7:04 PM Andrew Barnert wrote:
If you’re wondering whether integers are something you could define the laws of
complex algebra over, then no, it isn’t. For
On Oct 14, 2019, at 01:53, Chris Angelico wrote:
>
>> On Mon, Oct 14, 2019 at 7:04 PM Andrew Barnert wrote:
>> If you’re wondering whether integers are something you could define the laws
>> of complex algebra over, then no, it isn’t. For example, one of the laws is
>> that every number
On Mon, Oct 14, 2019 at 12:54:13AM -0700, Andrew Barnert via Python-ideas wrote:
> On Oct 13, 2019, at 22:54, Chris Angelico wrote:
> >
> > Mathematically, what's the difference between '1' and '1+0j' (or
> > '1+0i')?
>
> The details depend on what foundations you use, but let’s go with the
>
On Mon, 14 Oct 2019 at 05:47, Andrew Barnert via Python-ideas
wrote:
>
> `1 in complex` is _not_ mathematically true. Simplifying a bit, the elements
> of the algebra of complex numbers are ordered pairs of real numbers, and `1`
> is not a pair. When you’re working in, say, complex analysis,
>
> On Oct 13, 2019, at 22:54, Chris Angelico wrote:
> >
> > Mathematically, what's the difference between '1' and '1+0j' (or
> > '1+0i')?
>
1 is perfectly valid natural number, rational number (equivalent to 1/1),
real number (equivalent to 1.0) and complex number (equivalent to
1.0+0.0i).
On Mon, Oct 14, 2019 at 7:04 PM Andrew Barnert wrote:
> If you’re wondering whether integers are something you could define the laws
> of complex algebra over, then no, it isn’t. For example, one of the laws is
> that every number besides 0 has a multiplicative inverse, which obviously
> isn’t
Sorry, missed this part:
On Oct 13, 2019, at 22:54, Chris Angelico wrote:
isinstance(1, numbers.Complex)
> True
>
> Explain the difference?
`Complex` is an abstract type that defines an interface, which is loosely:
supporting all the complex-arithmetic operators, properties like `real`,
On Oct 13, 2019, at 22:54, Chris Angelico wrote:
>
> Mathematically, what's the difference between '1' and '1+0j' (or
> '1+0i')?
The details depend on what foundations you use, but let’s go with the most
common construction.
The natural number 1 is defined as 0 U {0}. Because 0 is defined as
On Mon, Oct 14, 2019 at 3:46 PM Andrew Barnert via Python-ideas
wrote:
>
> On Oct 13, 2019, at 18:39, Steven D'Aprano wrote:
> >
> > Even when the class can be identified as equivalent to
> > its set of values, such as for numeric types, there are all sorts of
> > complexities that will only
On Oct 13, 2019, at 18:39, Steven D'Aprano wrote:
>
> Even when the class can be identified as equivalent to
> its set of values, such as for numeric types, there are all sorts of
> complexities that will only lead to confusion:
>
>from numbers import Real
>1.0 in Real # okay,
On Sun, Oct 13, 2019 at 07:15:09PM -, Steve Jorgensen wrote:
> …and that leaves only the suggestion that `type.__contains__(self,
> other)` could be a synonym for `isinstance(other, self)`.
We don't normally think of an instance as being an element contained by
its class. We wouldn't say
This isn't really the same thing as enum since it has nothing to do with
numeric values. Per Andrew, however, `__contains__` actually does exactly what
I was asking for.
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On Mon, Oct 14, 2019 at 12:18 AM Steve Jorgensen wrote:
> class BrightColorsMeta(type):
> def __rin__(self, other):
> other.startswith('bright ')
>
> class BrightColors(metaclass=BrightColorsMeta): pass
>
> 'red' in BrightColors # -> False
> 'bright blue' in
On Oct 13, 2019, at 02:38, Steve Jorgensen wrote:
>
> Note that I'm new to this system, so I'm not sure if this will format
> correctly or whether I'll be able to edit it afterward to format it properly
> if not. Fingers crossed.
>
> Examples:
>import re
>from collections import
On Sun, Oct 13, 2019, at 14:51, David Mertz wrote:
> I would not want to overload plain strings' .__contains__() method to
> mean "has this substring OR matches this compiled regex." Besides being
> on a likely performance path, it's too special. And what about glob
> patterns, for example?
You make an excellent point. I withdraw that from my list of proposed cases.
…and that leaves only the suggestion that `type.__contains__(self, other)`
could be a synonym for `isinstance(other, self)`.
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I would not want to overload plain strings' .__contains__() method to mean
"has this substring OR matches this compiled regex." Besides being on a
likely performance path, it's too special. And what about glob patterns,
for example? Those too?
But you can wrap your strings in
I see that __contains__ is not a new thing, so I'm not sure why I didn't notice
it. Thanks very much for pointing it out. :)
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Hello,
For your last example you have the __contains__ special methods.
Le dim. 13 oct. 2019 à 15:18, Steve Jorgensen a écrit :
> Note that I'm new to this system, so I'm not sure if this will format
> correctly or whether I'll be able to edit it afterward to format it
> properly if not.
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