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
> >>
> >>
> >
>
>
>
>
