Answer / kiran

you have SET INTERFACE in COLLECTION in java . where u can
store unique elements and if u try to add duplicate elements
it will raise an error

Answer / indresh_ips

Hey, Here is the program of Unique ArrayList.........
Just Run It........

import java.util.*;
class ArrayListUnique {

static public ArrayList uniqueArrayList(ArrayList arrl) {
int i;
for(int k=0;k<arrl.size();k++) {
Object s=arrl.get(k);
i=Collections.frequency(arrl,s);

for(int j=1;j<i;j++) {

arrl.remove(s);
}
}
return arrl;
}
public static void main (String[] args) {
ArrayList al= new ArrayList();

al.add("A");
al.add("A");
al.add("B");
al.add("C");
al.add("B");
al.add("A");
al.add("D");
al.add("D");
al.add("D");
al.add("D");
al.add("A");
al.add("B");
al.add("F");
al.add("G");
al.add("G");
al.add(10);
al.add(5);
al.add(10);
al.add(5);
System.out.println ("Before declaring unique:"+al);

ArrayList a=ArrayListUnique.uniqueArrayList(al);

System.out.println ("after declaring unique: "+a);
}
}

Answer / sudhakar

I have modified the above program. And made esay the
process.


import java.util.ArrayList;

public class UniqueArrayListValues {

static ArrayList assignValues() {
ArrayList a1 = new ArrayList();
a1.add("A");
a1.add("B");
a1.add("C");
a1.add("27");
a1.add("A");
a1.add("B");
a1.add("C");
a1.add("27");
a1.add("A");
a1.add("B");
a1.add("C");
a1.add("27");
return a1;
}

static ArrayList applyUniqueKey(ArrayList a1) {
ArrayList a2 = new ArrayList();
for (int i = 0; i < a1.size(); i++) {
if (!a2.contains(a1.get(i))) {
a2.add(a1.get(i));
}
}
return a2;
}

public static void main(String args[]) {
ArrayList beforeUniqueKey = assignValues();
System.out.println("Before applying Unique
Key:" + beforeUniqueKey);
ArrayList afterUniqueKey = applyUniqueKey
(beforeUniqueKey);
System.out.println("Afrer applying Unique
Key:" + afterUniqueKey);
}

}

Answer / surya chandra mohan , visakhap

small modification for first program. But that one is really excellent.i really proud Indresh_ips.


import java.util.*;
class ArrayListUnique2 {

static public ArrayList uniqueArrayList(ArrayList arrl) {
int i;
String check="";
for(int k=0;k<arrl.size();k++) {
String s=arrl.get(k).toString();


if(!check.contains(s)){
check = check+s+", ";
}else{
arrl.remove(s);
}
}
return arrl;
}
public static void main (String[] args) {
ArrayList al= new ArrayList();

al.add("A");
al.add("A");
al.add("B");
al.add("C");
al.add("B");
al.add("A");
al.add("D");
al.add("D");
al.add("D");
al.add("D");
al.add("A");
al.add("B");
al.add("F");
al.add("G");
al.add("G");
al.add(10);
al.add(5);
al.add(10);
al.add(5);
System.out.println ("Before declaring unique:"+al);

ArrayList a=ArrayListUnique.uniqueArrayList(al);

System.out.println ("after declaring unique: "+a);
}
}

Answer / amar

Excalent work friend

Answer / ballu

i think java does not this in built facility ... you would
need to make sure that objects inserted in array are unique
( by overriding equals() and hash() method of Object class

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