Re: [Python-ideas] Make partial a built-in

On 21 September 2016 at 02:42, Ryan Gonzalez wrote: > Most often, when I see lambdas used for this, it looks like: > > lambda *args, **kw: myfunc(partial_arg, *args, **kw) Wrapper functions like that are almost always more readable when written as named functions: def

Re: [Python-ideas] Make partial a built-in

אלעזר wrote: @partial(partial, partial(partial, partial)) def add(a, b, c): return a + b + c For large numbers of arguments, it's much clearer if you write it this way: >>> from functools import partial as badger, partial as mushroom >>> @badger(badger, badger(badger, badger(badger,

Re: [Python-ideas] Make partial a built-in

Folks, There are pros and cons of partial over lambda over classes, and which you prefer may be at least in part a matter of subjective taste. But Guido has spoken that he is virulently against making partial a builtin. It really isn't hard to put "from functools import partial" at the top

Re: [Python-ideas] Make partial a built-in

This class should be put somewhere. If you need it from inside a method, you have to choose where to put it. If it is inside the method, it forces the reader to scan it thoroughly to verify there's no "real" closure there, and it also makes your methods significantly longer. If it is outside the

Re: [Python-ideas] Make partial a built-in

On Tue, 20 Sep 2016 15:29:36 +, אלעזר wrote: > The alternative to partial is writing a closure in the form of a > function, that needs to be carefully inspected to verify that it is > indeed just a partial application and not something more complex. It > has more opportunity for introducing

Re: [Python-ideas] Make partial a built-in

On Wed, Sep 21, 2016 at 12:04 AM Terry Reedy wrote: > On 9/20/2016 11:51 AM, Guido van Rossum wrote: > > ... (The greater flexibility of lambda, pointed out by David Mertz, is > another.) > > I just wanted to point out that the greater flexibility of lambda is a very good

Re: [Python-ideas] Make partial a built-in

On 9/20/2016 11:51 AM, Guido van Rossum wrote: We seem to have fundamentally different ideas of what sort of code is most readable. The alternative to partial is usually a lambda, Partial and lambda are different in that partial captures variable values immediately, whereas lambda does not,

Re: [Python-ideas] Make partial a built-in

On Tue, Sep 20, 2016 at 9:18 PM Stephan Houben wrote: > I must admit I am a bit partial to partial, you can do fun things like > this: > > >>> from functools import partial > >>> @partial(partial, partial) > ... def add(x, y): > ... return x+y > ... > >>> add(3)(4) > 7

Re: [Python-ideas] Make partial a built-in

I must admit I am a bit partial to partial, you can do fun things like this: >>> from functools import partial >>> @partial(partial, partial) ... def add(x, y): ... return x+y ... >>> add(3)(4) 7 I suppose that isn't exactly going to convince Guide to put it in builtins, though. Stephan

Re: [Python-ideas] Make partial a built-in

I find myself "partializing" in ways partial() doesn't support more often than not. E.g. lambda first, third: myfunc(first, 42, third) I think it's good to have partial() in functools, but it's two orders of magnitude less common than things that should be in builtins. On Sep 20, 2016 9:42 AM,

Re: [Python-ideas] Make partial a built-in

Le 20 sept. 2016 18:42, "Ryan Gonzalez" a écrit : > Doing something like: > > lambda x, y: myfunc(partial_arg, x, y) > > is more error-prone to changes in myfunc's signature. No, if the signature of the function changes, then the signature of the partial would also change. The

Re: [Python-ideas] Make partial a built-in

On Tue, Sep 20, 2016 at 11:51 AM, Guido van Rossum wrote: > Also, I once timed it and could not show that partial was faster. This > surprised me but it was what I measured (in one particular case). I did similar timings on several occasions in the past and was also

Re: [Python-ideas] Make partial a built-in

On Tue, Sep 20, 2016 at 8:29 AM, אלעזר wrote: > Guido, can you please elaborate? > > "What's going on" is usually that the same arguments are going to be > passed over and over again, and the programmer wanted to avoid this > repetition. The other option is adjusting the

Re: [Python-ideas] Make partial a built-in

Guido, can you please elaborate? "What's going on" is usually that the same arguments are going to be passed over and over again, and the programmer wanted to avoid this repetition. The other option is adjusting the function to a predefined interface. The alternative to partial is writing a

Re: [Python-ideas] Make partial a built-in

I am radically opposed to this proposal. Every time I see a partial application I wonder endlessly about what's going on. --Guido (mobile) ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code

Re: [Python-ideas] Make partial a built-in

On Tue, Sep 20, 2016 at 09:56:48AM +, אלעזר wrote: > foo.__call__.partial() solves most of the problem I think. There are two problems with that, one obvious and one subtle. The obvious one is that __call__ is a dunder method, which means that accessing it directly from outside of the

Re: [Python-ideas] Make partial a built-in

Yeah I did say it was a strawman :) On Tue, Sep 20, 2016 at 11:17 AM Chris Angelico wrote: > On Tue, Sep 20, 2016 at 6:09 PM, אלעזר wrote: > > I meant something like making it a "__bind__" (just a strawman > suggestion) > > and do the same lookup as foo()

Re: [Python-ideas] Make partial a built-in

On Tue, Sep 20, 2016 at 10:54 AM Chris Angelico wrote: > On Tue, Sep 20, 2016 at 5:01 PM, אלעזר wrote: > > But the foo() finds the function to call, so foo.bind() could be made to > > find it too. > > class Demo: > def __init__(self): > self.bind

Re: [Python-ideas] Make partial a built-in

Hi all, I would like to add that I don't believe that discoverability is always better in the `builtins' module. I personally had the experience of going over itertools, where I found 'zip_longest', but I couldn't find a 'zip_shortest'. Only after some googling I found out it was called `zip'

Re: [Python-ideas] Make partial a built-in

But the foo() finds the function to call, so foo.bind() could be made to find it too. בתאריך יום ג׳, 20 בספט' 2016, 08:24, מאת Stefan Behnel ‏: > אלעזר schrieb am 19.09.2016 um 17:59: > > If at all, it should be function.bind(). It was discussed and dropped; I > > don't

Re: [Python-ideas] Make partial a built-in

אלעזר schrieb am 19.09.2016 um 17:59: > If at all, it should be function.bind(). It was discussed and dropped; I > don't remember why, but one problem is that it looks like an in-place > modification. IMHO, the main drawback of that solution is that it only works for functions and not for any