On Thu, Apr 2, 2015 at 8:22 AM, Peter Uhnák <i.uhnak@gmail.com> wrote:
Hi,
I've just run into quite a nasty surprise ~~~~~~~~~~~~~~~~ col := #(1 2 3 4 5) asOrderedCollection. col do: [ :each | col remove: each. ]. col ~~~~~~~~~~~~~~~~ it throws "NotFound: nil not found in OrderedCollection" I tested it also in Pharo3 and there it just silently removed first, third and fifth element.
Looking at the implementation of OrderedCollection>>do: it seems that doing what I'm doing is a bad idea.
So what shall one do:? col copy do: [...] ?
Yes, as a general rule, do not modify a collection you are iterating on, so, doing col copy do: looks right. removeAllSuchThat: aBlock "Evaluate aBlock for each element and remove all that elements from the receiver for that aBlock evaluates to true. Use a copy to enumerate collections whose order changes when an element is removed (i.e. Sets)." self copy do: [:each | (aBlock value: each) ifTrue: [self remove: each]] If the collection is huge, that can be an issue.
Why can't do: be a bit smarter? Optimization?
If you have the group of things to remove you can do aCollection removeAll: anotherCollection Phil
Thanks, Peter