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Re: iterate and delete

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<malcolm.mclean5@btinternet.com> wrote in message 
news:72265d42-b411-47e2-bd5b-8b4929059354@googlegroups.com...
> On Monday, May 6, 2013 7:13:35 PM UTC+1, bob wrote:
>> Does computer science in general ever address the issue of when you are
>> iterating over a collection and deleting elements from it?  If you are 
>> just
>> using a counter, this can be tricky as the deletions can mess up the 
>> indices.
>>
> It's something that people who teach computer science in universities are
> well aware of.
> However it tends to be glossed over at an introductory level to avoid
> overloading students with difficulties. Deleting or, more rarely, adding
> elements can make it very difficult to keep iterators up to date.

Surely it's impossible to deal with it in general? Since any collection 
could be transformed, in between one iteration and the next, into a totally 
different collection. The current position or element in the old collection 
might then be meaningless.

-- 
Bartc

 

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iterate and delete bob <bob@coolfone.comze.com> - 2013-05-06 11:13 -0700
  Re: iterate and delete JJ <duh@nah.meh> - 2013-05-07 03:35 +0700
  Re: iterate and delete Rui Maciel <rui.maciel@gmail.com> - 2013-05-07 09:39 +0100
    Re: iterate and delete bob <bob@coolfone.comze.com> - 2013-05-08 07:54 -0700
  Re: iterate and delete malcolm.mclean5@btinternet.com - 2013-05-09 07:58 -0700
    Re: iterate and delete "BartC" <bc@freeuk.com> - 2013-05-09 22:53 +0100

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