Re: removing elements while looping with an index, and return values from Set add

[Paul Johnson]

Removing an item with [oldList remove: thisElem] breaks the index that 
is based on the list.  For cases like yours, you should use the remove 
method of the index itself, because the index is aware of the change.
[newList addLast: [index remove]];
No matter what we had in the Swarm User Guide, your for() loop is the 
recomended way to traverse a collection because it does not stop on nils.

Ken Gosier wrote:
> 2 questions about a simple sim I'm coding up:
>
> I'm sure the first question is an RTFM question, so if I can get a pointer
> to the proper FM to R, I'd be most grateful. :) Anyway, I'm using an index
> to loop over a List, and I want to remove elements which test positive for
> a certain condition:
>
> id <List> newList = [List create: self];
> id <Index> index = [oldList begin: self];
> id thisElem;
>
> for (thisElem=[index next]; [index getLoc]==Member; thisElem=[index next])
> {
>    if (  condition  )
>    {
>       [newList addLast: [oldList remove: thisElem]];
>    }
> }
> [index drop];



--
Paul E. Johnson                       email: address@hidden
Dept. of Political Science            http://lark.cc.ku.edu/~pauljohn
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66045                FAX: (785) 864-5700


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