Deleting duplicate strings in array

Question

At one point it compares array(1)compareto(array(1)) is this a problem? Amount birds is the amount of elements in array. I am trying to remove duplicate string in the array. Is it fixable or should i re approach.

for (i = 0; i <= amountBirds - 1; i++)
{
    for (x = 1; x <= amountBirds; x++)
    {
        duplicate = birdArray[i].compareTo(birdArray[x]);

        if (duplicate == 0)
        {
            birdArray[i] = birdArray[x];
        }
    }
}

Instead of compareTo, why not use indexOf to find the existing elements — Saurabh Tiwari
– Saurabh Tiwari, Commented Jun 7, 2017 at 7:20
Why not use Java Collection objects instead of an array? Example — Jacob
– Jacob, Commented Jun 7, 2017 at 7:23
I had been out of touch with Java for years now. But I believe I used indexOf sometime back. Hava a look here stackoverflow.com/questions/4962361/… — Saurabh Tiwari
– Saurabh Tiwari, Commented Jun 7, 2017 at 7:25

Prabhav · Accepted Answer · 2017-06-07 07:27:14Z

2

Try this:

birdArray = new HashSet<String>(Arrays.asList(birdArray)).toArray(new String[0]);

answered Jun 7, 2017 at 7:27

Prabhav

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5 Comments

JC101 Over a year ago

Hi I actually set birdArray as a global variable, im not exactly sure how i should word that, here it is: public static String[] birdArray = new String[50];

Prabhav Over a year ago

just put above code at place of your comparison for loops.

Prabhav Over a year ago

and add this lines in imports ---> import java.util.HashSet; import java.util.Arrays;

JC101 Over a year ago

:o it did something ill keep working at it thank you, it basically removed one of the elements in the array and also has a blank array element. But at same time does not accept duplicates if i enter one.

Prabhav Over a year ago

ya, HasSet can not have duplicates as you need.

Abhilash Arjaria · Accepted Answer · 2017-06-07 07:27:18Z

2

Try Set or LinkedHashSet . Convert your arraylist into Set , It will automatically remove the duplicate from List as Set does not allow Duplicate value. but Remember it is a Collection rather than a List.

answered Jun 7, 2017 at 7:27

Abhilash Arjaria

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1 Comment

JC101 Over a year ago

I think i need a bit more resarch never heard of set or hashset aha.. but thank you

idarak · Accepted Answer · 2017-06-07 08:01:28Z

2

Either you can include a if check before using compareTo method

if ( i != x ) {
        duplicate = birdArray[i].compareTo(birdArray[x]);
}

Or you can use Set in Java Collection library. This approach does not allow duplicate entries to be inserted. So at the time of insertion itself, you can avoid the duplicates.

Or you keep the birdArray as it is. And use a Set as a mediator to insert and remove the duplicates.

Set<String> birdSet = new LinkedHashSet<String>(); //to keep the order of the birds
for (i = 0; i < amountBirds; i++)
{
    birdSet.add (birdArray[i]);
}
birdArray = Arrays.copyOf(birdSet.toArray(), birdSet.size(), String[].class);

edited Jun 7, 2017 at 8:01

answered Jun 7, 2017 at 7:45

idarak

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1 Comment

JC101 Over a year ago

ahh i understand what you mean now, i like first option ill try and think aha

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