[Python-ideas] Temporary variables in comprehensions

As far as I can see, a comprehension like alist = [f(x) for x in range(10)] is better than a for-loop for x in range(10): alist.append(f(x)) because the previous one shows every element of the list explicitly so that we don't need to handle `append` mentally. But when it comes to something

Re: [Python-ideas] Give ipaddresses an __index__ method

On Thu, Feb 15, 2018 at 01:39:13PM +1000, Nick Coghlan wrote: > There are tests that ensure IP addresses don't implement __index__, > and the pragmatic reason for that is the downside you mentioned: to > ensure they can't be used as indices, slice endpoints, or range > endpoints. If it is an

Re: [Python-ideas] Boolean ABC similar to what's provided in the 'numbers' module

On Wed, Feb 14, 2018 at 5:49 PM, Chris Barker - NOAA Federal < chris.bar...@noaa.gov> wrote: > > > > So as long as you are not expecting to ever need mypy you should be fine > -- however if you're sharing code at some point someone is probably going > to want to point mypy at it. > > mypy isn’t

Re: [Python-ideas] Give ipaddresses an __index__ method

On Thu, 15 Feb 2018 15:14:03 +1100, Steven D'Aprano wrote: > On Thu, Feb 15, 2018 at 11:45:46AM +1100, Chris Angelico wrote: > >> Except that this computer's IPv4 is not 3232235539, and I never want >> to enter it that way. I enter it as 192.168.0.19 - as four separate >> integers. > > That's

Re: [Python-ideas] Give ipaddresses an __index__ method

On Thu, Feb 15, 2018 at 3:14 PM, Steven D'Aprano wrote: > On Thu, Feb 15, 2018 at 11:45:46AM +1100, Chris Angelico wrote: > >> Except that this computer's IPv4 is not 3232235539, and I never want >> to enter it that way. I enter it as 192.168.0.19 - as four separate >>

Re: [Python-ideas] Give ipaddresses an __index__ method

On Thu, Feb 15, 2018 at 11:45:46AM +1100, Chris Angelico wrote: > Except that this computer's IPv4 is not 3232235539, and I never want > to enter it that way. I enter it as 192.168.0.19 - as four separate > integers. That's partly convention (and a useful convention: it is less error- prone

Re: [Python-ideas] Extending __format__ method in ipaddress

On 15 February 2018 at 08:29, Eric Osborne wrote: > Nick Coghlan suggested I instead extend __format__, which is what the > diffs in the current pull request do. This allows a great deal more > flexibility: the current code takes 'b', 'n', or 'x' types, as well as the > '#'

Re: [Python-ideas] Give ipaddresses an __index__ method

On 15 February 2018 at 10:18, Steven D'Aprano wrote: > This idea is inspired by Eric Osborne's post "Extending __format__ > method in ipaddress", but I wanted to avoid derailing that thread. > > I notice what seems to be an inconsistency in the ipaddress objects: > > py> v4 =

Re: [Python-ideas] Extending __format__ method in ipaddress

On 02/14/2018 02:29 PM, Eric Osborne wrote: Nick Coghlan suggested I instead extend __format__, which is what the diffs in the current pull request do. This allows a great deal more flexibility: the current code takes 'b', 'n', or 'x' types, as well as the '#' option and support for the '_'

Re: [Python-ideas] Boolean ABC similar to what's provided in the 'numbers' module

> > So as long as you are not expecting to ever need mypy you should be fine -- > however if you're sharing code at some point someone is probably going to > want to point mypy at it. mypy isn’t an “official” tool, but PEP484 is — and mypy is more or less a reference implimentation, yes? mypy

Re: [Python-ideas] Give ipaddresses an __index__ method

On Thu, Feb 15, 2018 at 11:18 AM, Steven D'Aprano wrote: > This idea is inspired by Eric Osborne's post "Extending __format__ > method in ipaddress", but I wanted to avoid derailing that thread. > > I notice what seems to be an inconsistency in the ipaddress objects: > > py>

[Python-ideas] Give ipaddresses an __index__ method

This idea is inspired by Eric Osborne's post "Extending __format__ method in ipaddress", but I wanted to avoid derailing that thread. I notice what seems to be an inconsistency in the ipaddress objects: py> v4 = ipaddress.IPv4Address('1.2.3.4') py> bin(v4) Traceback (most recent call last):

Re: [Python-ideas] Boolean ABC similar to what's provided in the 'numbers' module

No, PyCharm has its own annotation checker, which is much more lenient than mypy (and less compliant with PEP 484). And indeed the runtime checkers are also unrelated (though a runtime checker will have to work with the type objects created by typing.py). So as long as you are not expecting to

Re: [Python-ideas] Boolean ABC similar to what's provided in the 'numbers' module

I see :) This does not seem to happen with PyCharm IDE + Anaconda distribution. Is PyCharm relying on MyPy under the hood ? I actually have no knowledge at all about MyPy and how it relates to PyCharm static code analysis warnings. I’m pretty sure though that the runtime checkers (enforce,

Re: [Python-ideas] Boolean ABC similar to what's provided in the 'numbers' module

I am mystified how you can be using the numbers package with mypy. Example: import numbers def f(a: numbers.Integral, b: numbers.Integral) -> numbers.Integral: return a + b f(12, 12) This gives an two errors on the last line when checked by mypy: _.py:10: error: Argument 1 to "f" has

Re: [Python-ideas] Boolean ABC similar to what's provided in the 'numbers' module

The main use case I had in mind was PEP484-based type hinting/checking actually: def my_function(foo: Boolean): pass explicitly states that my_function accepts any Boolean value, whether it is a python bool or a np.bool that would come from a numpy array or pandas dataframe. Note that type

Re: [Python-ideas] Boolean ABC similar to what's provided in the 'numbers' module

Can you show some sample code that you have written that shows where this would be useful? Note that using the numbers package actually makes static type checking through e.g. mypy difficult. So I presume you are talking about dynamic checking? --Guido On Feb 14, 2018 12:42 AM, "Sylvain MARIE"

Re: [Python-ideas] Boolean ABC similar to what's provided in the 'numbers' module

My point is just that today, I use the ‘numbers’ package classes (Integral, Real, …) for PEP484 type-hinting, and I find it quite useful in term of input type validation (in combination with PEP484-compliant type checkers, whether static or dynamic). Adding a Boolean ABC with a similar behavior