Remove duplicates and sort comma seperated string 2

[hard2bhumble]

Think I posted this in the wrong forum previously .......

I am trying to remove duplicates from a comma separated list and sort it alphabetically. I'm not sure of the best method. I have achieved what I want the long way, but I think I should be able to use a Sorted Set, list or collection to achieve the same thing far more efficiently.
does anyone have any suggestions?
(e.g.) One, Five, Seven, One, Three, Four --> One, Three, Four, Five, Seven

 

[wangdong]

Here is an example.

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class StringSort {
	public static void main(String args[]){
		String tmp="One,Five,Seven,One,Three,Four";
		String []target=tmp.split(",");
		Set<String> set = new HashSet<String>();
		Arrays.sort(target);
		for(int i=0;i<target.length;i++){
			set.add(target[i]);
		}
		
		System.out.println(set.toString());
			
	}
}

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[Diancecht]

Well, that will sort the alphabetically, you'll need some more work to do what you need.

Byw, you will need Java 1.5 to compile the program above.

Cheers,
Dian

 

[Miros]

I think instead of building the HashSet, I'd just loop through the array doing the output after ensuring that the current item is not equal to the previous item.

        String temp2 = "" ;
        for(int i=0;i<target.length;i++){
            if ( temp2 != target[i] )
            {
                 System.out.println( target[i] ) ;
                 temp2 = target[i] ;
            }
        }

All that HashSet stuff has to be slower than one variable assignment!

 

[sedj]

No no no ! You are comparing pointers there, not the actual string data !

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[Diancecht]

sedj means you need to use the equals method to compare Strings.

Cheers,
Dian

 

[timw]

I usually use the compareTo() method. I've had problems in the past using equals() on Strings.

Tim

 

[Diancecht]

What kind of problems?

Cheers,
Dian

 

[timw]

If I remember, we were getting equals() returning false for two strings which were definitely identical. One of the Strings may have been demarshalled from a remote J2EE application, don't know if this would have any bearing on the matter.

Tim

 

[Diancecht]

Never heard about such a thing. Looking at the source code for both methos, I find them exact expect a type check: equals checks is the object compared is a String.

Maybe you were doing something 'cute' with classloaders, but from my experience, the equals methos is reliable and more explicit than compareTo because it returns a boolean and you don't need to remeber if 0 was equality or not.

Cheers,
Dian

 

[timw]

...something 'cute' with classloaders.

Come to think about it, I recall that the code was inside a Stateless Session Bean hosted by a Borland Enterprise Server. Classloaders would definitely feature I think.

Maybe I should go back to using the equals() method for normal use.

Tim

 

[wangdong]

Yes, I think if you are trying to implement your class from the Object class, you have to override two methods compareTo() and HashCode(), this will avoid your problem.

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[Diancecht]

You cannot override Strings, they're final objects.

Cheers,
Dian

 

[chrissie1]

two strings which were definitely identical

Perhaps you were trying to compare "chrissie1" to "chrissie1" and those are never identical.

Christiaan Baes
Belgium

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