Re: Copying collection without duplicates

From:

Patricia Shanahan <pats@acm.org>

Newsgroups:

comp.lang.java.programmer

Date:

Sat, 11 Aug 2007 13:12:12 -0700

Message-ID:

<f9l56t$163t$1@ihnp4.ucsd.edu>

Daniel Dyer wrote:

On Sat, 11 Aug 2007 20:01:10 +0100, Patricia Shanahan <pats@acm.org> wrote:

Karsten Wutzke wrote:

On 11 Aug., 00:29, Danno <dh.evolutionn...@gmail.com> wrote:

On Aug 10, 8:30 am, Karsten Wutzke <kwut...@web.de> wrote:

Is there any faster way without overriding other methods?
Karsten

Yep!

Set<?> uniqueCollection = new TreeSet(collection);

Hmm how does this skip duplicates?

A set contains no duplicates, so if the collection were the list "A",
"B", "A" the treeset would contain "A", "B". However, the TreeSet
iterator is in compareTo order, not the List order.

A LinkedHashSet may be preferable if preserving the order is important:

http://java.sun.com/j2se/1.5.0/docs/api/java/util/LinkedHashSet.html

I don't think LinkedHashSet has the ability to addAll at a specified
index. The following is a quote from the original article:

I have the following method overriding Collection.addAll:

@Override
public boolean addAll(int index, Collection<? extends E> cln)
{

Collection does not have a two argument addAll. List does, so I suspect
the new class is supposed to implement List.

Patricia