Den 11.03.2010 01:54, skrev Nicolas Cellier:
> 2010/3/11 Igor Stasenko <[email protected]>:
>
>> On 10 March 2010 15:07, Nicolas Cellier
>> <[email protected]> wrote:
>>
>>> self collect: aBlock as: Set
>>>
>>>
>> One more time, i found this very beatiful and useful extension to
>> Collection protocol.
>> And i am proud being a witness when this thing is born! :)
>>
>>
> Yes,
> I remember saying I was not convinced some times ago...
> http://lists.squeakfoundation.org/pipermail/squeak-dev/2008-June/129457.html
> Being able to change own opinion is a good thing !
>
> Nicolas
>
I have to admit, I still don't quite see what's wrong with
1.
(self collect: aBlock) asSet
or
2.
mySet := Set new: self size.
self do: aBlockAddingToMySetAtEnd.
or (well, this one is IMO indeed a bit ugly)
3.
self inject: (Set new:self size) into:
[ :sub :next |
sub add: next collectValue; yourself ] ...
Sure, they're a bit verbose, and when you'd like to use 1 vs 2 or 3
varies abit on the collection contents, but they all work in all
dialects, and aren't THAT much longer, unless your collect block is
really short.
Cheers,
Henry
>
>>> 2010/3/10 Mariano Martinez Peck <[email protected]>:
>>>
>>>> Hi. I was needing something like the SQL select distinct, that doesn't take
>>>> into account repeated objects. I didn't found anything useful in
>>>> Collection,
>>>> and thus, I have implemented this:
>>>>
>>>> Collection >> collectDistinct: aBlock
>>>>
>>>>
>>>> collectDistinct: aBlock
>>>> "Evaluate aBlock with each of the receiver's elements as the argument.
>>>> Collect the resulting values into a Set, thus repeated objects will not
>>>> be present.
>>>> Answer the new collection."
>>>>
>>>> | newSet |
>>>> newSet := self species new asSet.
>>>> self do: [:each | newSet add: (aBlock value: each)].
>>>> ^ newSet
>>>>
>>>>
>>>> Is there a better way ? Do you think it make sense to put this in Pharo ?
>>>>
>>>> Cheers
>>>>
>>>> Mariano
>>>>
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>>>>
>>>>
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>>
>>
>> --
>> Best regards,
>> Igor Stasenko AKA sig.
>>
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