Re: How do you iterate over a List and remove elements?

From:

Patricia Shanahan <pats@acm.org>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 24 Aug 2007 09:37:16 -0700

Message-ID:

<13cu29t3mij2k7a@corp.supernews.com>

Manish Pandit wrote:

On Aug 24, 8:51 am, Patricia Shanahan <p...@acm.org> wrote:

What is the purpose of the list.contains(obj) pre-check?

My bad..did not realize contains returns a boolean. Been thinking
about this for a while, and I was wondering if it makes sense to use
an array (or another list..a clone) as an intermediatory. I know this
has scalability and performance numbers against it though. Here is a
little snippet:

         ArrayList<Integer> list = new ArrayList<Integer>();
         for(int i=0; i<10; i++){
                  list.add(i);
         }
         //remove all the even numbers
         Integer[] array = new Integer[list.size()];
         list.toArray(array);
         for( int i:array ){
             if( i%2==0 ) {
                 list.remove(new Integer(i));
             }
         }
         System.out.println(list);

Ofcourse this needs to be synchronized, to make sure the array and the
list do not go out of sync.

-cheers,
Manish

What is the advantage of this, compared to the really dumb, simple,
obvious approach using the Iterator remove() method?

      //remove all the even numbers
      Iterator<Integer> it = list.iterator();
      while(it.hasNext()){
        if(it.next() % 2 == 0){
          it.remove();
        }
      }

Patricia