Re: How to check variables for uniqueness ?

From:

John Ersatznom <j.ersatz@nowhere.invalid>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 21 Dec 2006 01:33:27 -0500

Message-ID:

<emd9s6$cns$1@aioe.org>

Andrew Thompson wrote:

Patricia Shanahan wrote:

Andrew Thompson wrote:

krisl...@gmail.com wrote:
...

I have eight variables : var1, var2... var 8. All types String.
How to check that each variables has unique values ?

One way would be to create a Map, iterate the
var's and if not present in the map, add the value
as a key, else return false.

...

Any particular reason for Map, rather than Set?

You mean besides, 'lack of enough consultation
of the relevant docs.'? ;-)

Note that the result of a Set add call is true if, and only if, the
value is not already in the Set.

A Set sounds the go - it is just right for this task.

HashSet<String> foo = new HashSet<String>();
foo.add(var1);
foo.add(var2);
foo.add(var3);
foo.add(var4);
foo.add(var5);
foo.add(var6);
foo.add(var7);
foo.add(var8);
if (foo.size() < 8)
duplicateExists();
else
duplicateDoesNotExist();

If you actually need to identify the specific duplicate pairs, you need
to compare them one by one -- 1 with all the others, 2 with all the
higher-numbered ones, and so on up to 7 and 8, using equals().

If you want case insensitivity, use e.g.

foo.add(var3.toLowerCase());

or equalsIgnoreCase().