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Removing duplicates from an array

Posted on 2008-10-25
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Last Modified: 2010-04-21
Hi guys,

I have a file from which I'm reading a Point objects.  I put them into an array, and I need to remove any duplicates.  I think my code should work, but when I check the elements in the array, duplicates are still there. Can you please provide some feedback on what I'm doing wrong?

p.s. The code to initially fill the array works, the only problem that I have is that the duplicates are not being removed. (Lines 8 to 10)
public void fillArray(){
			array = new Point[this.arraySize()];
                        String line = fileReader.readLine();
			for(int i=0; line!=null; i++){
				array[i] = this.convertPoint(line);
                                line = fileReader.readLine();
			}
			List<Point> list = Arrays.asList(array);
			Set<Point> set = new HashSet<Point>(list);
			array = (Point[])set.toArray(new Point[]{});
	}

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Question by:ubuntuguy
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4 Comments
 
LVL 60

Expert Comment

by:Kevin Cross
ID: 22805908
The Point must be able to be compared if I am not mistaken as the Set/HashSet will not allow duplicates, but it must have some way to tell if one Point object is equal to another Point object in order to work.
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Assisted Solution

by:Kevin Cross
Kevin Cross earned 800 total points
ID: 22805938
If it is true that lines that are equal create Points that are equal and different lines create different Points, then this should work.

(my code may not be all the way correct, just threw it together to give you the overall concept -- you should be able to use as a basis for correcting code)

good luck.


public void fillArray(){
    Set<String> set = new HashSet<String>();
    String line = fileReader.readLine();
    for(int i=0; line!=null; i++){
        set.add(line);
        line = fileReader.readLine();
    }
    
    List<Point> list = new List<Point>();
    Iterator<String> it = set.iterator();
    while (it.hasNext()) {
        list.add(this.convertPoint(it.next());
    }
    
    array = list.toArray(array);
}

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Accepted Solution

by:
chaitu chaitu earned 1200 total points
ID: 22806041
i have written a simple example which will remove dupliactes.may be it will help you.

      String[] strArray = new String[]{"Object","Array","Converted","List","List"};
               
                        
                List list = Arrays.asList(strArray);
               
                  Set<Point> set = new HashSet<Point>(list);
                  strArray = (String[])set.toArray(new String[]{});
                  for (int i = 0; i < strArray.length; i++) {
                        System.out.println(strArray[i]);      
                  }
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LVL 1

Author Closing Comment

by:ubuntuguy
ID: 31510033
Thanks guys, chaituu solution worked very well for strings, then I simply put the array of string into a new array converting each string into a point.
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