On Thu, Apr 2, 2015 at 8:22 AM, Peter Uhnák <i.uh...@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 >
