I am still not convinced.
> On 6 Mar 2019, at 19:24, Tim Mackinnon <tim@testit.works> wrote:
>
> I still am tempted to make asDictionary work - because the the moment you get
> a #key , DNU error - which is definitely not right.
The error might not be super clear, but it is not wrong, the elements of your
collection do not respond to #key, a necessity to create a dictionary from a
collection of associations/pairs.
Also, if you modify #asDictionary like that, then
<some bag> as: #Dictionary
will still fail.
This is all not so simple as it seems.
> So should Bag asDictionary give you a reasonable dictionary, or should it
> throw a proper exception - something like:
>
> DomainError signal: ‘#asDictionary not supported, use #valueAndCounts’
>
> Is that better - or do we accept that it inherits it from Collection and so
> can do something useful?
>
> Tim
>
>> On 6 Mar 2019, at 18:11, p...@highoctane.be wrote:
>>
>> And when asking the object:
>>
>> #(1 2 4 5 6 7 2 1 4 3) asBag isDictionary
>>
>> we get false. So, not, not a dictionary.
>>
>> I still have been using #valuesAndCounts to get the dictionary out of a bag
>> on several occasions.
>>
>> And is useful indeed.
>>
>> #(1 2 4 5 6 7 2 1 4 3) asBag occurrencesOf: 2
>>
>> and
>>
>> #(1 2 4 5 6 7 2 1 4 3) asBag valuesAndCounts at: 2
>>
>> seem pretty much the same.
>>
>> But in this age of streams/reactive streams and lazy evaluations, what do we
>> have in Pharo on that front?
>>
>> Phil
>>
>>
>>
>>
>>
>> On Wed, Mar 6, 2019 at 4:49 PM Sven Van Caekenberghe <s...@stfx.eu> wrote:
>> I was just explaining how it is now, what I think the rationale is behind it.
>>
>> I understand #asDictionary as working on a collection of pairs/associations
>> (because it basically goes to #withAll:).
>>
>> A bag is just a collection that is optimised for many duplicates, the fact
>> that you have values and counts is more an implementation detail than an
>> intrinsic property.
>>
>> The conversion that you want, and that already exists in #valuesAndCounts is
>> one interpretation of what a bag is, not the only one. A bag is foremost a
>> collection of things.
>>
>> I am not immediately convinced that #valuesAndCounts should be the default
>> #asDictionary interpretation.
>>
>> What about the inverse for example ?
>>
>> { #foo->2. #bar->3 } asDictionary asBag.
>>
>> But this is certainly an interesting discussion.
>>
>> > On 6 Mar 2019, at 16:23, Tim Mackinnon <tim@testit.works> wrote:
>> >
>> > As Richard said - as a bag is relationship between keys and frequencies, I
>> > would expect it to be able to convert to a dictionary.
>> >
>> > It displays in an inspector just like a Dictionary - which is why I
>> > figured I could convert to pass it back to the exercise that was written
>> > with Dictionaries in mind.
>> >
>> > <PastedGraphic-3.png>
>> >
>> >
>> > The code to fix it is quite simple, but on these kinds of things - I
>> > thought it worth checking before submitting a PR.
>> >
>> > Tim
>> >
>> >
>> >> On 6 Mar 2019, at 13:53, Sven Van Caekenberghe <s...@stfx.eu> wrote:
>> >>
>> >> Why would that work ? What would you expect the output to be ?
>> >>
>> >> Try:
>> >>
>> >> #(1 2 3) asDictionary
>> >>
>> >> it fails in exactly the same way. You need key/value pairs (Associations).
>> >>
>> >> These do work
>> >>
>> >> Bag new add: #foo->100; asDictionary.
>> >>
>> >> Bag new addAll: 'ABABABAAAA'; valuesAndCounts.
>> >>
>> >>> On 6 Mar 2019, at 14:25, Tim Mackinnon <tim@testit.works> wrote:
>> >>>
>> >>> I was surprised to find that a Bag can’t convert to a dictionary - e.g.
>> >>>
>> >>> Bag new
>> >>> addAll: 'aabbbbcddd’;
>> >>> asDictionary
>> >>>
>> >>> Gives an error - Dnu #key
>> >>>
>> >>>
>> >>> It looks to me like Bag is inheriting a bad version of #associationsDo:
>> >>> and instead could simply forward it to #doWithOccurences: instead?
>> >>>
>> >>> I know Bag is not used that much - but it comes up a lot in programming
>> >>> exercises.
>> >>>
>> >>> Tim
>> >>
>> >>
>> >
>>
>>
>>
>
