I would like to get unique values from two Collection objects. How would I do that?
Example: Let us take two ArrayLists:
List bag1 = new ArrayList();
List bag2 = new ArrayList();
bag1.add("1");
bag1.add("2");
bag1.add("3");
bag1.add("7");
bag1.add("8");
bag1.add("9");
bag2.add("4");
bag2.add("5");
bag2.add("6");
bag2.add("7");
bag2.add("8");
bag2.add("9");
I need to get a result like --> 1,2,3 from bag1 and 4,5,6 from bag2
Could you please help me out?
Two things:
You should take a look at Sets instead. The Java Collection has a few classes which deal with this. The idea is you could just the the set difference between the two collections, and you'll get your answer.
Use a 'set' to store your data. That way your collection will have unique elements as and when you add elements to the set.
See the javadoc over here: http://docs.oracle.com/javase/1.4.2/docs/api/java/util/Set.html
have you tried...
bag1.removeAll(bag2);
If you want to keep bag1 and bag2 intact you can use a Set variable and pass all values of bag1 into the Set and then check for contains() like
Set set = new HashSet();
set.addAll(bag2);
for(Object o: bag1){
if(!set.contains(o)){
// Do whatever you want with bag1 elements
}
}
set.clear();
set.addAll(bag1);
for(Object o: bag2){
if(!set.contains(o)){
// Do whatever you want with bag2 elements
}
}
Use the removeAll method define in the Set interface.
Set intersect = new TreeSet(bag1);
intersect.removeAll(bag2);
List unique1 = Arrays.asList(intersect);
intersect = new TreeSet(bag2);
intersect.removeAll(bag1);
List unique2 = Arrays.asList(intersect);