Checking if values are the same

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francan00@yahoo.com - 28 Oct 2007 19:16 GMT

I currently have two String objects I check to find out if they are
the same value:

String str1 = "red";
String str2 = "yellow";
if (str1.equals(str2)){
System.out.println("Equal");
}
else{
System.out.println("Not equal");
}

Now I need to check 10 objects. How would I check 10 objects to find
out if any of them have the same value?

Please advise.

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Are Nybakk - 28 Oct 2007 19:31 GMT

> I currently have two String objects I check to find out if they are
> the same value:
[quoted text clipped - 12 lines]
>
> Please advise.

Couldn't you just iterate through a String array? Or add the Strings to
two collections and check equality that way?

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Are Nybakk - 28 Oct 2007 23:25 GMT

>> I currently have two String objects I check to find out if they are
>> the same value:
[quoted text clipped - 15 lines]
> Couldn't you just iterate through a String array? Or add the Strings to
> two collections and check equality that way?

I think I misunderstood somewhat - should be one collection and you can
check if it contains your string.

Lew's solution, however, is quite elegant.

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Lew - 28 Oct 2007 19:36 GMT

> I currently have two String objects I check to find out if they are
> the same value:
[quoted text clipped - 10 lines]
> Now I need to check 10 objects. How would I check 10 objects to find
> out if any of them have the same value?

Variations on:

Collection <Thing> mightHaveDupes = getSomeCollection();
Collection <Thing> noDupes = new WhateverCollection <Thing> ();
// we'll get back to which Collection implementation to use

for ( Thing thing : mightHaveDupes )
{
if ( noDupes.contains( thing ))
{
log( "Thing {"+ thing +"} is duplicated." );
}
else
{
noDupes.add( thing );
}
}

If the copy is a Set, then duplication is avoided automatically:

public <T> boolean hasDupes( Collection<T> mayHave )
{
Set<T> copy = new HashSet<T> ( mayHave );
return (copy.size() < mayHave.size());
}

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Lew

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francan00@yahoo.com - 28 Oct 2007 21:12 GMT

> franca...@yahoo.com wrote:
> > I currently have two String objects I check to find out if they are
[quoted text clipped - 42 lines]
> --
> Lew

Thanks, I dont have Generics in my Java 1.4 environment.

How would this be without Generics?

public <T> boolean hasDupes( Collection<T> mayHave )
{
Set<T> copy = new HashSet<T> ( mayHave );
return (copy.size() < mayHave.size());

}

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Patricia Shanahan - 28 Oct 2007 21:18 GMT

...

> How would this be without Generics?
>
[quoted text clipped - 4 lines]
>
> }

Just delete all instances of "<T>".

Patricia

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Daniel Pitts - 28 Oct 2007 20:26 GMT

> I currently have two String objects I check to find out if they are
> the same value:
[quoted text clipped - 12 lines]
>
> Please advise.

The easiest way would probably be to add them to a Set of some sort
(HashSet probably). Set.add() will return false if that value was
already in the set.

Signature

Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>

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Roedy Green - 28 Oct 2007 23:58 GMT

>Now I need to check 10 objects. How would I check 10 objects to find
>out if any of them have the same value?

You want an array of Strings. You compare each of them against the
first one. See http://mindprod.com/jgloss/array.html

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Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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Checking if values are the same

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