when you send #asSortedCollection: the result is a new sorted collection. You printed the original sorted collection and it used the default sort-block.
If you want to use a SortedCollection you can create it via SortedCollection sortBlock:[:a :b | a x < b x].
If you then add objects to it, the collection will always sort itself.
You can also start by creating some other collection and sort it later, using the #sorted: method. #sorted: will also return a new collection. If you call #sort: on a collection it’ll try to sort the collection itself (that may work on OrderedCollections and Arrays).
Personally i’ve never used a SortedCollection and just took whatever i had at hand and sent #sorted: at the end of it.
Instead of using sort-blocks i encourage you to try sort functions, they’re a lot easier to understand.
For sorting the points you can also use aCollection sorted:#x ascending. To combine sort-functions you can simply use the #, method. You can also use single-argument blocks instead of symbols like:
aCollectionOfPoints sorted:#x ascending , [:point | point y * point r] descending.
Kind Regards
Karsten
--
Georg Heeg eK - Köthen
Handelsregister: Amtsgericht Dortmund A 12812
Am Mittwoch, 27. November 2013 um 11:11 schrieb lhhuong:
I have an example as below:
*obj:= SortedCollection new:3.
obj add: 7@5.
obj add: 2@4.
obj add: 25@1.
obj asSortedCollection:[
:point1 :point2 | point1 x < point2 x.
].
Transcript cr.
Transcript show: (obj ) printString.*
and the result: *SortedCollection (25 @ 1 2 @ 4 7 @ 5)*
The collection does not sort by x.
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