Re: Suggestion: make sequence and map interfaces more similar

On Friday, April 1, 2016 at 1:58:29 PM UTC+5:30, Tim Golden wrote: > > For the latter, I take the view that I know where the delete key is (or > the "ignore thread" button or whatever) and I just skip the thread when > it shows up. > Feel free to contact the list owner [python list-owner] if >

Re: Suggestion: make sequence and map interfaces more similar

Steven D'Aprano : > On Fri, 1 Apr 2016 07:27 pm, Tim Golden wrote: > >> FWIW I'm broadly with Antoon here: wider-ranging discussions can be >> interesting and useful. > > Sure. But sometimes conversations are going nowhere: That's why GNUS has the "k" command to wipe out a

Re: Suggestion: make sequence and map interfaces more similar

On Fri, 1 Apr 2016 07:27 pm, Tim Golden wrote: > FWIW I'm broadly with Antoon here: wider-ranging discussions can be > interesting and useful. Sure. But sometimes conversations are going nowhere: http://www.youtube.com/watch?v=kQFKtI6gn9Y http://www.montypython.net/scripts/argument.php

Re: Suggestion: make sequence and map interfaces more similar

On 01/04/2016 08:59, Antoon Pardon wrote: Op 31-03-16 om 16:12 schreef Mark Lawrence via Python-list: On 31/03/2016 14:27, Random832 wrote: So can we discuss how a unified method to get a set of all valid subscripts (and/or subscript-value pairs) on an object would be a useful thing to have

Re: Suggestion: make sequence and map interfaces more similar

On 01/04/2016 08:59, Antoon Pardon wrote: > Op 31-03-16 om 16:12 schreef Mark Lawrence via Python-list: >> On 31/03/2016 14:27, Random832 wrote: >>> So can we discuss how a unified method to get a set of all valid >>> subscripts (and/or subscript-value pairs) on an object would be a useful >>>

Re: Suggestion: make sequence and map interfaces more similar

> On Mar 31, 2016, at 10:02 AM, Marko Rauhamaa wrote: > > However, weirdly, dicts have get but lists don't. Read PEP 463 for discussion on this topic. https://www.python.org/dev/peps/pep-0463/ -- https://mail.python.org/mailman/listinfo/python-list

Re: Suggestion: make sequence and map interfaces more similar

Op 31-03-16 om 16:12 schreef Mark Lawrence via Python-list: > On 31/03/2016 14:27, Random832 wrote: >> So can we discuss how a unified method to get a set of all valid >> subscripts (and/or subscript-value pairs) on an object would be a useful >> thing to have without getting bogged down in

Re: Suggestion: make sequence and map interfaces more similar

On 3/31/2016 10:13 AM, Marko Rauhamaa wrote: One could compose a table of correspondences: with some corrections --- list (L)dict (D) --- L[key] = value

Re: Suggestion: make sequence and map interfaces more similar

Jussi Piitulainen : > operator.itemgetter(*selector)(fields) # ==> ('y', 'y', 'x') > > [...] > > operator.itemgetter(*selector)(field_dict) # ==> ('y', 'y', 'x') > > It's not quite the same but it's close and it works the same for > strings, lists, dicts, ... Not

Re: Suggestion: make sequence and map interfaces more similar

Random832 : > So can we discuss how a unified method to get a set of all valid > subscripts (and/or subscript-value pairs) on an object would be a > useful thing to have without getting bogged down in theoretical > claptrap about the meaning of the mapping contract? One

Re: Suggestion: make sequence and map interfaces more similar

On 31/03/2016 14:27, Random832 wrote: On Thu, Mar 31, 2016, at 09:17, Mark Lawrence via Python-list wrote: On 31/03/2016 14:08, Antoon Pardon wrote: Op 31-03-16 om 13:57 schreef Chris Angelico: Okay. I'll put a slightly different position: Prove that your proposal is worth discussing by

Re: Suggestion: make sequence and map interfaces more similar

Chris Angelico : > Or, even more likely and even more Pythonic: > [fields[i] for i in selector] > ['y', 'y', 'x'] > > As soon as you get past the easy and obvious case of an existing > function, filter and map quickly fall behind comprehensions in utility > and readability.

Re: Suggestion: make sequence and map interfaces more similar

On Thursday, March 31, 2016 at 6:38:56 PM UTC+5:30, Antoon Pardon wrote: > Op 31-03-16 om 13:57 schreef Chris Angelico: > > Okay. I'll put a slightly different position: Prove that your proposal > > is worth discussing by actually giving us an example that we can > > discuss. So far, this thread

Re: Suggestion: make sequence and map interfaces more similar

On Thu, Mar 31, 2016, at 09:17, Mark Lawrence via Python-list wrote: > On 31/03/2016 14:08, Antoon Pardon wrote: > > Op 31-03-16 om 13:57 schreef Chris Angelico: > >> Okay. I'll put a slightly different position: Prove that your proposal > >> is worth discussing by actually giving us an example

Re: Suggestion: make sequence and map interfaces more similar

On 31/03/2016 14:08, Antoon Pardon wrote: Op 31-03-16 om 13:57 schreef Chris Angelico: Okay. I'll put a slightly different position: Prove that your proposal is worth discussing by actually giving us an example that we can discuss. So far, this thread has had nothing but toy examples (and

Re: Suggestion: make sequence and map interfaces more similar

On 31/03/2016 13:49, Marco Sulla via Python-list wrote: On 31 March 2016 at 14:30, Mark Lawrence via Python-list wrote: Note that dict also supports __getitem__() and __len__(), but is considered a mapping rather than a sequence because the lookups use arbitrary

Re: Suggestion: make sequence and map interfaces more similar

On Fri, Apr 1, 2016 at 12:08 AM, Antoon Pardon wrote: > Op 31-03-16 om 13:57 schreef Chris Angelico: >> Okay. I'll put a slightly different position: Prove that your proposal >> is worth discussing by actually giving us an example that we can >> discuss. So far, this

Re: Suggestion: make sequence and map interfaces more similar

Op 31-03-16 om 13:57 schreef Chris Angelico: > Okay. I'll put a slightly different position: Prove that your proposal > is worth discussing by actually giving us an example that we can > discuss. So far, this thread has had nothing but toy examples (and > bogoexamples that prove nothing beyond

Re: Suggestion: make sequence and map interfaces more similar

Marko Rauhamaa writes: > Chris Angelico wrote: > >> Okay. I'll put a slightly different position: Prove that your >> proposal is worth discussing by actually giving us an example that we >> can discuss. > > Sorry for missing most of the arguments here, but if you are talking > about treating

Re: Suggestion: make sequence and map interfaces more similar

I want also to add that we are focusing on sequences, but my proposal is also to make map interface more similar, introducing a vdict type that iterates over values, and this will be for me really more practical. PEP 234 ( http://legacy.python.org/dev/peps/pep-0234/ ) never convinced me. Van

Re: Suggestion: make sequence and map interfaces more similar

On Thu, Mar 31, 2016 at 11:36 PM, Marko Rauhamaa wrote: > Chris Angelico : > >> On Thu, Mar 31, 2016 at 10:22 PM, Antoon Pardon >> wrote: >> Okay. I'll put a slightly different position: Prove that your proposal >> is worth

Re: Suggestion: make sequence and map interfaces more similar

Chris Angelico : > On Thu, Mar 31, 2016 at 10:22 PM, Antoon Pardon > wrote: > Okay. I'll put a slightly different position: Prove that your proposal > is worth discussing by actually giving us an example that we can > discuss. Sorry for missing

Re: Suggestion: make sequence and map interfaces more similar

On 31/03/2016 12:58, Marco Sulla via Python-list wrote: On 31 March 2016 at 04:40, Steven D'Aprano wrote: Enough of the hypothetical arguments about what one could do or might do. Let's see a concrete example of actual real world code used in production, not a mickey-mouse

Re: Suggestion: make sequence and map interfaces more similar

On 31 March 2016 at 04:40, Steven D'Aprano wrote: > Enough of the hypothetical arguments about what one could do or might do. > Let's see a concrete example of actual real world code used in production, > not a mickey-mouse toy program, where it is desirable that adding or >

Re: Suggestion: make sequence and map interfaces more similar

On Thu, Mar 31, 2016 at 10:22 PM, Antoon Pardon wrote: > Op 31-03-16 om 12:36 schreef Steven D'Aprano: >> On Thu, 31 Mar 2016 06:52 pm, Antoon Pardon wrote: >> >>> it is your burden to argue that problem. >> No it isn't. I don't have to do a thing. All I need to do

Re: Suggestion: make sequence and map interfaces more similar

Op 31-03-16 om 12:36 schreef Steven D'Aprano: > On Thu, 31 Mar 2016 06:52 pm, Antoon Pardon wrote: > >> it is your burden to argue that problem. > No it isn't. I don't have to do a thing. All I need to do is sit back and > wait as this discussion peters off into nothing. The burden isn't on me to

Re: Suggestion: make sequence and map interfaces more similar

Op 31-03-16 om 12:36 schreef Steven D'Aprano: > On Thu, 31 Mar 2016 06:52 pm, Antoon Pardon wrote: > >> it is your burden to argue that problem. > No it isn't. I don't have to do a thing. If that is how you think about this, why do you contribute? I completly understand if you are of the opinion

Re: Suggestion: make sequence and map interfaces more similar

On Thu, 31 Mar 2016 06:52 pm, Antoon Pardon wrote: > it is your burden to argue that problem. No it isn't. I don't have to do a thing. All I need to do is sit back and wait as this discussion peters off into nothing. The burden isn't on me to justify the status quo. The burden is on those who

Re: Suggestion: make sequence and map interfaces more similar

Op 31-03-16 om 04:44 schreef Steven D'Aprano: > On Thu, 31 Mar 2016 03:52 am, Random832 wrote: > >> Like, these are common patterns: >> >> for i, x in enumerate(l): >># do some stuff, sometimes assign l[i] >> >> for k, v in d.items(): >># do some stuff, sometimes assign d[k] > > for a, b

Re: Suggestion: make sequence and map interfaces more similar

Op 31-03-16 om 04:40 schreef Steven D'Aprano: > On Thu, 31 Mar 2016 06:07 am, Antoon Pardon wrote: > >>> Because fundamentally, it doesn't matter whether dicts are surjections or >>> not. They're still many-to-one mappings, and those mappings between keys >>> and values should not change due to

Re: Suggestion: make sequence and map interfaces more similar

On Thursday 31 March 2016 13:45, Paul Rubin wrote: > Steven D'Aprano writes: >> I want to see an actual application where adding a new key to a .^ >> mapping is expected to change the other keys. > directory["mary.roommate"] = "bob" >

Re: Suggestion: make sequence and map interfaces more similar

Steven D'Aprano writes: > I want to see an actual application where adding a new key to a > mapping is expected to change the other keys. directory["mary.roommate"] = "bob" directory["mary.address"] = None # unknown address ... directory["bob.address"] = "132 Elm Street"

Re: Suggestion: make sequence and map interfaces more similar

On Thu, 31 Mar 2016 03:52 am, Random832 wrote: > Like, these are common patterns: > > for i, x in enumerate(l): ># do some stuff, sometimes assign l[i] > > for k, v in d.items(): ># do some stuff, sometimes assign d[k] for a, b in zip(spam, eggs): # do some stuff, sometimes assign

Re: Suggestion: make sequence and map interfaces more similar

On Thu, 31 Mar 2016 06:07 am, Antoon Pardon wrote: >> Because fundamentally, it doesn't matter whether dicts are surjections or >> not. They're still many-to-one mappings, and those mappings between keys >> and values should not change due to the insertion or deletion of >> unrelated keys. > >

Re: Suggestion: make sequence and map interfaces more similar

On 30/03/2016 21:00, Marco Sulla via Python-list wrote: Let me also add that even if it seems that my idea will not break any official contracts, I can create a new ABC class and let maps and sequence types inherit from it. IMHO it's absolutely not needed, but at least the discussion will be no

Re: Suggestion: make sequence and map interfaces more similar

On 30/03/2016 20:35, Marco Sulla via Python-list wrote: On 30 March 2016 at 02:55, Terry Reedy wrote: To me [seq.items() and seq.keys()] are useless and confusing duplications since enumerate()(seq) and range(len(seq)) are quite different from dict.items and dict.keys.

Re: Suggestion: make sequence and map interfaces more similar

Let me also add that even if it seems that my idea will not break any official contracts, I can create a new ABC class and let maps and sequence types inherit from it. IMHO it's absolutely not needed, but at least the discussion will be no more distracted my secondary considerations, since the

Re: Suggestion: make sequence and map interfaces more similar

On 30 March 2016 at 02:55, Terry Reedy wrote: > To me [seq.items() and seq.keys()] are useless and confusing duplications > since enumerate()(seq) > and range(len(seq)) are quite different from dict.items and dict.keys. It's true. Indeed IMHO it's enumerate() that will be a

Re: Suggestion: make sequence and map interfaces more similar

Op 30-03-16 om 17:56 schreef Steven D'Aprano: > On Thu, 31 Mar 2016 12:12 am, Antoon Pardon wrote: > >> Op 30-03-16 om 14:22 schreef Steven D'Aprano: > > [...] >>> Why is a mapping (such as a dict) best described as a surjection? >>> Consider: >>> >>> d = {1: None, 2: 'a', 3: 'b', 4: None} >>>

Re: Suggestion: make sequence and map interfaces more similar

This discussion is getting a bit distracted from the original request. Let's look at it from a higher level. What is being requested, regardless of if you call it a "map interface" or whatever, is a single way, for sequences and maps... broadly, anything with a __getitem__, to iterate over all

Re: Suggestion: make sequence and map interfaces more similar

On Wed, 30 Mar 2016 11:50 pm, Random832 wrote: > Absolutely nothing is stable under a *completely unrestricted* set of > operations. Yes, you're absolutely correct. If I create a Python dict, {1: 'a'}, and then smash the computer to smithereens with a 50lb sledge hammer, neither the key nor the

Re: Suggestion: make sequence and map interfaces more similar

On Thu, 31 Mar 2016 12:12 am, Antoon Pardon wrote: > Op 30-03-16 om 14:22 schreef Steven D'Aprano: [...] >> Why is a mapping (such as a dict) best described as a surjection? >> Consider: >> >> d = {1: None, 2: 'a', 3: 'b', 4: None} >> >> >> Every key has exactly one value. There are no values

Re: Suggestion: make sequence and map interfaces more similar

Marko Rauhamaa writes: > Steven D'Aprano: > >> On Wed, 30 Mar 2016 10:21 pm, Jussi Piitulainen wrote: >>> Ok, safer to say that some many-to-one mappings are not surjective. >> >> Can you give an example of a Python dict which is not surjective? > > Depends on the codomain. The values() method

Re: Suggestion: make sequence and map interfaces more similar

Steven D'Aprano writes: > On Wed, 30 Mar 2016 10:21 pm, Jussi Piitulainen wrote: > >> Ok, safer to say that some many-to-one mappings are not surjective. > > Can you give an example of a Python dict which is not surjective? Can you give an example of a mapping which is not surjective? Can you

Re: Suggestion: make sequence and map interfaces more similar

On 03/30/16 at 03:55pm, Marko Rauhamaa wrote: > Manolo Martínez : > > > On 03/30/16 at 02:44pm, Marko Rauhamaa wrote: > >> I don't even know if you can say much about the cardinality (or > >> countability) of mappings. The general set of mappings can't exist. > >> The

Re: Suggestion: make sequence and map interfaces more similar

Op 30-03-16 om 14:22 schreef Steven D'Aprano: > On Wed, 30 Mar 2016 09:28 pm, Jussi Piitulainen wrote: > >> Steven D'Aprano writes: >> >>> On Wed, 30 Mar 2016 06:12 pm, Jussi Piitulainen wrote: >>> Steven D'Aprano writes: > Given a surjection (many-to-one mapping) No. And I

Re: Suggestion: make sequence and map interfaces more similar

Manolo Martínez : > On 03/30/16 at 02:44pm, Marko Rauhamaa wrote: >> I don't even know if you can say much about the cardinality (or >> countability) of mappings. The general set of mappings can't exist. >> The *class* of mappings does exist in some set theories, but I

Re: Suggestion: make sequence and map interfaces more similar

On Wed, Mar 30, 2016, at 01:43, Steven D'Aprano wrote: > This is not an argument about dicts being mutable, because clearly they > aren't. This is an argument about key:value pairs being stable. "Stable" > doesn't mean "immutable". If you change the value associated with a key > directly, then

Re: Suggestion: make sequence and map interfaces more similar

Steven D'Aprano : > On Wed, 30 Mar 2016 10:21 pm, Jussi Piitulainen wrote: >> Ok, safer to say that some many-to-one mappings are not surjective. > > Can you give an example of a Python dict which is not surjective? Depends on the codomain. The values() method gives the

Re: Suggestion: make sequence and map interfaces more similar

On Wed, 30 Mar 2016 10:21 pm, Jussi Piitulainen wrote: > Ok, safer to say that some many-to-one mappings are not surjective. Can you give an example of a Python dict which is not surjective? Or an example of something which obeys the Mapping ABC which is not surjective? Artificial and

Re: Suggestion: make sequence and map interfaces more similar

On 03/30/16 at 02:44pm, Marko Rauhamaa wrote: > Jussi Piitulainen : > > > Manolo Martínez writes: > >> On 03/30/16 at 01:40pm, Jussi Piitulainen wrote: > >>> Yes, and most many-to-one mappings are *not* surjective. > >> > >> Well, I don't know about most, there are

Re: Suggestion: make sequence and map interfaces more similar

On Wed, 30 Mar 2016 09:28 pm, Jussi Piitulainen wrote: > Steven D'Aprano writes: > >> On Wed, 30 Mar 2016 06:12 pm, Jussi Piitulainen wrote: >> >>> Steven D'Aprano writes: >>> Given a surjection (many-to-one mapping) >>> >>> No. And I doubt that Wikipedia says that. >> >> No to what? What

Re: Suggestion: make sequence and map interfaces more similar

Jussi Piitulainen : > Manolo Martínez writes: >> On 03/30/16 at 01:40pm, Jussi Piitulainen wrote: >>> Yes, and most many-to-one mappings are *not* surjective. >> >> Well, I don't know about most, there are uncountably many surjective >> and non-surjective

Re: Suggestion: make sequence and map interfaces more similar

Manolo Martínez writes: > On 03/30/16 at 01:40pm, Jussi Piitulainen wrote: >> Manolo Martínez writes: > > >> > I think it's with your definition of surjection. Bijections are >> > surjective, no? >> >> Yes, and most many-to-one mappings are *not* surjective. > > Well, I don't know about most,

Re: Suggestion: make sequence and map interfaces more similar

Antoon Pardon writes: > Op 30-03-16 om 12:28 schreef Jussi Piitulainen: >> Steven D'Aprano writes: >> >>> On Wed, 30 Mar 2016 06:12 pm, Jussi Piitulainen wrote: >>> Steven D'Aprano writes: > Given a surjection (many-to-one mapping) No. And I doubt that Wikipedia says that. >>>

Re: Suggestion: make sequence and map interfaces more similar

On 03/30/16 at 01:40pm, Jussi Piitulainen wrote: > Manolo Martínez writes: > > > I think it's with your definition of surjection. Bijections are > > surjective, no? > > Yes, and most many-to-one mappings are *not* surjective. Well, I don't know about most, there are uncountably many surjective

Re: Suggestion: make sequence and map interfaces more similar

Manolo Martínez writes: > On 03/30/16 at 09:17pm, Steven D'Aprano wrote: >> On Wed, 30 Mar 2016 06:12 pm, Jussi Piitulainen wrote: >> >> > Steven D'Aprano writes: >> > >> >> Given a surjection (many-to-one mapping) >> > >> > No. And I doubt that Wikipedia says that. >> >> >> No to what? What

Re: Suggestion: make sequence and map interfaces more similar

Op 30-03-16 om 12:28 schreef Jussi Piitulainen: > Steven D'Aprano writes: > >> On Wed, 30 Mar 2016 06:12 pm, Jussi Piitulainen wrote: >> >>> Steven D'Aprano writes: >>> Given a surjection (many-to-one mapping) >>> No. And I doubt that Wikipedia says that. >> No to what? What are you

Re: Suggestion: make sequence and map interfaces more similar

On 03/30/16 at 09:17pm, Steven D'Aprano wrote: > On Wed, 30 Mar 2016 06:12 pm, Jussi Piitulainen wrote: > > > Steven D'Aprano writes: > > > >> Given a surjection (many-to-one mapping) > > > > No. And I doubt that Wikipedia says that. > > > No to what? What are you disagreeing with? > I

Re: Suggestion: make sequence and map interfaces more similar

Steven D'Aprano writes: > On Wed, 30 Mar 2016 06:12 pm, Jussi Piitulainen wrote: > >> Steven D'Aprano writes: >> >>> Given a surjection (many-to-one mapping) >> >> No. And I doubt that Wikipedia says that. > > No to what? What are you disagreeing with? Surjection does not mean many-to-one

Re: Suggestion: make sequence and map interfaces more similar

On Wed, 30 Mar 2016 06:12 pm, Jussi Piitulainen wrote: > Steven D'Aprano writes: > >> Given a surjection (many-to-one mapping) > > No. And I doubt that Wikipedia says that. No to what? What are you disagreeing with? -- Steven -- https://mail.python.org/mailman/listinfo/python-list

Re: Suggestion: make sequence and map interfaces more similar

Op 30-03-16 om 07:43 schreef Steven D'Aprano: > Yes, we're all very impressed that you spotted the trivial and obvious > loophole that changing a key:value will change the key:value that you just > changed *wink* but that doesn't really move the discussion anywhere. > > This is not an argument

Re: Suggestion: make sequence and map interfaces more similar

Steven D'Aprano writes: > Given a surjection (many-to-one mapping) No. And I doubt that Wikipedia says that. -- https://mail.python.org/mailman/listinfo/python-list

Re: Suggestion: make sequence and map interfaces more similar

On 29/03/2016 23:29, Marco Sulla via Python-list wrote: Let me add that an items() and keys() for sequences will be also useful for day-by-day programming, since they will be a shortcut for enumerate(seq) and range(len(seq)) I cannot remember the last time I needed range(len(seq)) so I don't

Re: Suggestion: make sequence and map interfaces more similar

On Wednesday 30 March 2016 16:43, Steven D'Aprano wrote: > This is not an argument about dicts being mutable, because clearly they > aren't. Er, I meant *immutable*. Dicts aren't immutable. -- Steve -- https://mail.python.org/mailman/listinfo/python-list

Re: Suggestion: make sequence and map interfaces more similar

On Wednesday 30 March 2016 14:38, Random832 wrote: > On Tue, Mar 29, 2016, at 20:56, Chris Angelico wrote: >> The map contract is this: >> >> x = StrangeDict() >> x[123] = 456 >> ... >> assert x[123] == 456 >> >> Your mapping does violate the map contract. > > So, you can put *anything* in

Re: Suggestion: make sequence and map interfaces more similar

On Tue, Mar 29, 2016, at 20:56, Chris Angelico wrote: > The map contract is this: > > x = StrangeDict() > x[123] = 456 > ... > assert x[123] == 456 > > Your mapping does violate the map contract. So, you can put *anything* in that "..."? x = dict() x[123] = 456 x[123] = 789 assert x[123] ==

Re: Suggestion: make sequence and map interfaces more similar

On Wed, Mar 30, 2016 at 9:29 AM, Marco Sulla via Python-list wrote: > On 29 March 2016 at 16:31, Chris Angelico wrote: >> But the definition of a sequence, and likewise the definition of a >> mapping, goes deeper than that. A sequence has *relative*

Re: Suggestion: make sequence and map interfaces more similar

On 3/29/2016 6:29 PM, Marco Sulla via Python-list wrote: Let me add that an items() and keys() for sequences will be also useful for day-by-day programming, since they will be a shortcut for enumerate(seq) and range(len(seq)) To me they are useless and confusing duplications since

Re: Suggestion: make sequence and map interfaces more similar

On 29 March 2016 at 16:31, Chris Angelico wrote: > But the definition of a sequence, and likewise the definition of a > mapping, goes deeper than that. A sequence has *relative* stability; > if one item is at a lower index than another, it will continue to be > at a lower index,

Re: Suggestion: make sequence and map interfaces more similar

On Wed, Mar 30, 2016 at 1:08 AM, Antoon Pardon wrote: > Op 28-03-16 om 03:05 schreef Steven D'Aprano: >> When you add a new key:value to a dict, the other key:value pairs don't >> change. That is the whole point of a mapping! Of course you can >> deliberately change

Re: Suggestion: make sequence and map interfaces more similar

Op 28-03-16 om 03:05 schreef Steven D'Aprano: > On Mon, 28 Mar 2016 05:01 am, Marco S. wrote: > >> Steven D'Aprano wrote: >> >>> The point you might have missed is that treating lists as if they were >>> mappings violates at least one critical property of mappings: that the >>> relationship

Re: Suggestion: make sequence and map interfaces more similar

On Mon, 28 Mar 2016 05:01 am, Marco S. wrote: > Steven D'Aprano wrote: > >> The point you might have missed is that treating lists as if they were >> mappings violates at least one critical property of mappings: that the >> relationship between keys and values are stable. > > > This is true

Re: Suggestion: make sequence and map interfaces more similar

On 27/03/2016 19:01, Marco S. via Python-list wrote: Mark Lawrence wrote: I cannot see this happening unless you provide a patch on the bug tracker. However I suspect you can get the same thing by subclassing dict. Why don't you try it and let us know how you get on? The problem with a

Re: Suggestion: make sequence and map interfaces more similar

Steven D'Aprano wrote: > The point you might have missed is that treating lists as if they were > mappings violates at least one critical property of mappings: that the > relationship between keys and values are stable. This is true for immutable maps, but for mutable ones, you can simply do

Re: Suggestion: make sequence and map interfaces more similar

On Sat, 26 Mar 2016 11:18 am, Marco Sulla wrote: >> That's a very superficial similarity: a list ['a', 'b', 'x', 'y'] is >> something like a mapping {0: 'a', 1: 'b', 2: 'x', 3: 'y'}. Seems logical, >> since in both cases we write collection[2] and get 'x' back. Marco, it is considered polite to

Re: Suggestion: make sequence and map interfaces more similar

On 26/03/2016 00:35, Marco Sulla wrote: I'd like to see vdict implemented anyway. It can't break old code and add a map type that has a common interface with sequences. I cannot see this happening unless you provide a patch on the bug tracker. However I suspect you can get the same thing

Re: Suggestion: make sequence and map interfaces more similar

Peter Otten wrote: >> I noticed that the sequence types does not have these methods that the map >> types has: get(), items(), keys(), values(). >> It could seem useless to have them for sequences, but I think it will ease >> the creation of functions and methods that allow you to input a

Re: Suggestion: make sequence and map interfaces more similar

> That's a very superficial similarity: a list ['a', 'b', 'x', 'y'] is > something like a mapping {0: 'a', 1: 'b', 2: 'x', 3: 'y'}. Seems logical, > since in both cases we write collection[2] and get 'x' back. > > But think about it a bit more, and you will see that the behaviour is in > fact

Re: Suggestion: make sequence and map interfaces more similar

On Wed, 23 Mar 2016 06:54 am, Marco S. wrote: > I noticed that the sequence types does not have these methods that the map > types has: get(), items(), keys(), values(). > > It could seem useless to have them for sequences, That's putting it mildly. > but I think it will ease > the creation

Re: Suggestion: make sequence and map interfaces more similar

Marco S. via Python-list wrote: > I noticed that the sequence types does not have these methods that the map > types has: get(), items(), keys(), values(). > It could seem useless to have them for sequences, but I think it will ease > the creation of functions and methods that allow you to input

Suggestion: make sequence and map interfaces more similar

I noticed that the sequence types does not have these methods that the map types has: get(), items(), keys(), values(). It could seem useless to have them for sequences, but I think it will ease the creation of functions and methods that allow you to input a generic iterable as parameter, but