Re: [Python-ideas] Sorted lists

On 4/8/2019 4:48 PM, Barry Scott wrote: On 8 Apr 2019, at 19:37, Terry Reedy wrote: On 4/8/2019 5:40 AM, Steven D'Aprano wrote: On Mon, Apr 08, 2019 at 07:44:41AM +0100, Alex Chamberlain wrote: I think a better abstraction for a sorted list is a new class, which implements the Sequence

Re: [Python-ideas] Sorted lists

On Mon, 8 Apr 2019 at 22:07, Barry Scott wrote: > > > > > On 8 Apr 2019, at 19:37, Terry Reedy wrote: > > > > On 4/8/2019 5:40 AM, Steven D'Aprano wrote: > >> On Mon, Apr 08, 2019 at 07:44:41AM +0100, Alex Chamberlain wrote: > >>> I think a better abstraction for a sorted list is a new class,

Re: [Python-ideas] Sorted lists

> On 8 Apr 2019, at 19:37, Terry Reedy wrote: > > On 4/8/2019 5:40 AM, Steven D'Aprano wrote: >> On Mon, Apr 08, 2019 at 07:44:41AM +0100, Alex Chamberlain wrote: >>> I think a better abstraction for a sorted list is a new class, which >>> implements the Sequence protocol (and hence can be

Re: [Python-ideas] Built-in parsing library

@DavidMertz Each one of them takes a dramatically different approach to the defining a grammar they work more towards implementing well known standards like the BNF. well internally they might work different to parse etc. Abdur-Rahmaan Janhangeer Mauritius

Re: [Python-ideas] Sorted lists

On 4/8/2019 5:40 AM, Steven D'Aprano wrote: On Mon, Apr 08, 2019 at 07:44:41AM +0100, Alex Chamberlain wrote: I think a better abstraction for a sorted list is a new class, which implements the Sequence protocol (and hence can be used in a lot of existing list contexts), but only exposed

Re: [Python-ideas] Built-in parsing library

On Mon, Apr 8, 2019 at 12:02 AM Paul Moore wrote: > I would expect that the only reasonable way of getting a parsing > library in the stdlib would be to propose an established one from PyPI > to be moved into the stdlib Absolutely -- unlike some proposals, a stand-alone parsing lib could very

Re: [Python-ideas] Sorted lists

On Mon, Apr 8, 2019, 6:26 AM Steven D'Aprano wrote: > Given all the points already raised, I think that an explicit SortedList > might be more appropriate. > This one looks cool. I've read about it, but haven't used it: http://www.grantjenks.com/docs/sortedcontainers/ I think a "sort hint"

Re: [Python-ideas] Sorted lists

On Mon, Apr 8, 2019, 5:46 AM Paul Moore wrote: > Still not convinced this is safe enough to be worth it ;-) > I'm convinced it's NOT safe enough to be worth it. On the other hand, a sortedlist subclass that maintained its invariant (probably remembering a key) sounds cool. I think there are

Re: [Python-ideas] cli tool to print value, similar to pydoc

Steven D'Aprano wrote on 4/8/19 4:35 AM: > How will it know what object os is, without guessing, if you haven't > imported it? Like pydoc/help does it. I assume it splits by dots and imports the longest importable subsplit (try...except ImportError in a loop), then iteratively getattrs the

Re: [Python-ideas] Sorted lists

On 4/8/19 6:25 AM, Steven D'Aprano wrote: > On Mon, Apr 08, 2019 at 02:55:54AM -0700, Nathaniel Smith wrote: >> If only we had some kind of API that could compute multiple quantiles at >> the same time... > > You mean something like this? > > quartiles, quintiles, deciles, percentiles =

Re: [Python-ideas] Sorted lists

On Mon, 8 Apr 2019 at 11:27, Steven D'Aprano wrote: > > Fair enough, but does it help you feel a bit better about the feature if > we called it a "sort hint", and emphasized that it should only be used > in the same sort of APIs where you might allow the caller to pass > > already_sorted=True

Re: [Python-ideas] Sorted lists

On Mon, Apr 08, 2019 at 10:34:19AM +0100, Paul Moore wrote: > On Mon, 8 Apr 2019 at 10:10, Steven D'Aprano wrote: > > > Possibly the maintainer of bisect may decide that its not worth the > > change. But for the statistics module, I would certainly change the > > implementation of median() to

Re: [Python-ideas] Sorted lists

On Mon, Apr 08, 2019 at 02:55:54AM -0700, Nathaniel Smith wrote: > Right, by "doesn't affect" I meant "cannot get any benefit, even if their > code is modified". Ah, sorry I misunderstood you. > > # This only makes sense if data is a sequence (list) > > # not an iterator. > >

Re: [Python-ideas] Sorted lists

On Mon, Apr 8, 2019, 02:09 Steven D'Aprano wrote: > On Sun, Apr 07, 2019 at 08:26:24PM -0700, Nathaniel Smith wrote: > > On Sun, Apr 7, 2019 at 7:37 PM Steven D'Aprano > wrote: > > > There are quite a few important algorithms which require lists to be > > > sorted. For example, the bisect

Re: [Python-ideas] Sorted lists

On Mon, 8 Apr 2019 at 10:34, Steven D'Aprano wrote: > The median (and soon, quantiles) API says: > > I'm going to sort the list for you, whether you need it or > not, just in case you do. Hmm, I didn't see that mentioned in the docs. It makes a difference to my comment about behaviour

Re: [Python-ideas] Sorted lists

On Mon, Apr 08, 2019 at 07:44:41AM +0100, Alex Chamberlain wrote: > I think a better abstraction for a sorted list is a new class, which > implements the Sequence protocol (and hence can be used in a lot of > existing list contexts), but only exposed mutation methods that can > guarantee that

Re: [Python-ideas] Sorted lists

On Mon, 8 Apr 2019 at 10:10, Steven D'Aprano wrote: > Possibly the maintainer of bisect may decide that its not worth the > change. But for the statistics module, I would certainly change the > implementation of median() to look something vaguely like this: > > # was > data =

Re: [Python-ideas] Sorted lists

On Mon, Apr 08, 2019 at 03:18:53PM +1000, Cameron Simpson wrote: > If this is a publicly queriable value, is there any need to have a > dunder name at all? Why not just give lists a public is_sorted > attribute? I don't mind that. > I'm also not convinced the cost to every insert/append is

Re: [Python-ideas] Sorted lists

On Mon, Apr 08, 2019 at 01:31:14PM +1000, Cameron Simpson wrote: > __setitem__ concerns me, along with other modification methods: what > about subclasses(*)? Every existing subclass which overrides __setitem__ > now needs to grow code to maintain __issorted__ if they do not > themselves call

Re: [Python-ideas] Sorted lists

On Sun, Apr 07, 2019 at 08:26:24PM -0700, Nathaniel Smith wrote: > On Sun, Apr 7, 2019 at 7:37 PM Steven D'Aprano wrote: > > There are quite a few important algorithms which require lists to be > > sorted. For example, the bisect module, and for statistics median and > > other quantiles. > > But

Re: [Python-ideas] cli tool to print value, similar to pydoc

On Mon, 8 Apr 2019 at 08:30, Daniel Bradburn wrote: > > Could it be q that you are thinking about? Thanks, but no - that's debug output in your code. The tool I recall was much more like the OP's suggestion > foo sys.version 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit

Re: [Python-ideas] Sorted lists

looks for me that means that all subclass of list has to maintain the __isorted__ invariant, looks like not a backward compatible modification and quite problematic in case of the invariant broken. So if I'm correct the design is brittle. Moreover, that solve only the strict subset of sort case

Re: [Python-ideas] cli tool to print value, similar to pydoc

Could it be q that you are thinking about? Op ma 8 apr. 2019 om 09:10 schreef Paul Moore : > On Sun, 7 Apr 2019 at 12:44, Thomas Gläßle wrote: > > There is already a tool like this on PyPI [1] (sadly py2 only atm), but > > if you agree that this is a common

Re: [Python-ideas] Sorted lists

Basically, I like this idea and of course theoretically it has use cases. But in the proposed form, it feels strongly curtailed. In practice, what does it mean to be sorted? [('a', 1),('b', 2),('bb', 4),('aaa', 3)] # Is this list sorted? [('a', 1),('aaa', 3),('b', 2),('bb', 4)] # or this?

Re: [Python-ideas] cli tool to print value, similar to pydoc

On Sun, 7 Apr 2019 at 12:44, Thomas Gläßle wrote: > There is already a tool like this on PyPI [1] (sadly py2 only atm), but > if you agree that this is a common pattern, I believe it would be a lot > more useful to have it in the stdlib. There's another tool on PyPI, I think, that does all you

Re: [Python-ideas] Built-in parsing library

On Mon, 8 Apr 2019 at 02:54, Nam Nguyen wrote: > Back to my original goal, I've gathered that there is some interest in having > a more general parser library in the stdlib. "Some", but not "much". Should I > start out with a straw proposal so that we can hash it out further? I would expect

Re: [Python-ideas] Sorted lists

On Mon, 8 Apr 2019 at 06:19, Cameron Simpson wrote: > > On 08Apr2019 00:17, Terry Reedy wrote: > >On 4/7/2019 10:32 PM, Steven D'Aprano wrote: > >>There are quite a few important algorithms which require lists to be > >>sorted. [...] > >>Proposal: let's give lists a dunder flag, __issorted__,