Mailman 3 September 2018 - Python-ideas

Add recordlcass to collections module
by Martin Bammer 03 Sep '18

03 Sep '18

Hi, what about adding recordclass (https://bitbucket.org/intellimath/recordclass) to the collections module It is like namedtuple, but elements are writable and it is written in C and thus much faster. And for convenience it could be named as namedlist. Regards, Martin

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Why shouldn't Python be better at implementing Domain Specific Languages?
by James Lu 03 Sep '18

03 Sep '18

Why shouldn't Python be better at implementing Domain Specific Languages? >From Johnathan Fine: > I really do wish we could have language that had all of Ruby's > strengths, and also all of Python's. That would be really nice. Quite > something indeed. > Languages do influence each other. Ruby is good at internal Domain > Specific Languages (DSLs). And there's Perrotta's influential book on > Ruby Metaprogramming. That's something I think Python could learn > from. > But I don't see any need (or even benefit) in adding new language > features to Python, so it can do better at DSLs. It would be nice if there was a DSL for describing neural networks (Keras). The current syntax looks like this: model.add(Dense(units=64, activation='relu', input_dim=100)) model.add(Dense(units=10, activation='softmax'))

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Re: [Python-ideas] Fix some special cases in Fractions?
by Jeroen Demeyer 03 Sep '18

03 Sep '18

On 2018-08-30 06:39, Neil Girdhar wrote: > I'd like these to be Fraction(1), Fraction(1), and Fraction(0). Why? I cannot think of any natural use case why you would want Fractions for a few special cases on an operation which returns non-Fractions generically. I consider it a feature to know in advance the type of the output of an operation, given the types of the input. Having an unexpected type suddenly show up because you happen to hit a special case is a recipe for bugs. Jeroen.

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Re: [Python-ideas] Add recordlcass to collections module
by Thautwarm Zhao 01 Sep '18

01 Sep '18

> > > ---------- Forwarded message ---------- > From: Martin Bammer <mrbm74(a)gmail.com> > To: python-ideas(a)python.org > Cc: > Bcc: > Date: Sat, 1 Sep 2018 09:47:04 +0200 > Subject: [Python-ideas] Add recordlcass to collections module > Hi, > > what about adding recordclass > (https://bitbucket.org/intellimath/recordclass) to the collections module > > It is like namedtuple, but elements are writable and it is written in C > and thus much faster. > > And for convenience it could be named as namedlist. > > Regards, > > Martin > > There are a problem which prevent you to reach your goals. As list in Python is already that efficient, a wrapper of this list in C to supply so-called namedlist interface could not be that efficient. Member accessing in Python bytecode requires looking up corresponding attribute in a hashtable, if you want to access a list by attribute, actually there is an overhead. This is nothing to do with C implementation. See https://docs.python.org/3/library/dis.html#opcode-LOAD_ATTR

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Re: [Python-ideas] Add recordlcass to collections module
by Angus Hollands 01 Sep '18

01 Sep '18

> > From: "Steven D'Aprano" <steve(a)pearwood.info> > To: python-ideas(a)python.org > Cc: > Bcc: > Date: Sat, 1 Sep 2018 18:25:21 +1000 > Subject: Re: [Python-ideas] Add recordlcass to collections module > On Sat, Sep 01, 2018 at 09:47:04AM +0200, Martin Bammer wrote: > > Hi, > > > > what about adding recordclass > > (https://bitbucket.org/intellimath/recordclass) to the collections > module > > The first thing you need to do is ask the author of that library whether > or not he or she is willing to donate the library to the Python stdlib, > which (among other things) means keeping to the same release schedule as > the rest of the stdlib. > > > > It is like namedtuple, but elements are writable and it is written in C > > and thus much faster. > > Faster than what? > > > > And for convenience it could be named as namedlist. > > Why? Is it a list? > > How or why is it better than dataclasses? > > > -- > Steve > > _______________________________________________ > Python-ideas mailing list > Python-ideas(a)python.org > https://mail.python.org/mailman/listinfo/python-ideas It would need to be a list of the members are mutable. As to the other questions, yes, do we need another module in the standard library?Angus > >

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