Can collection.sort display output in descending order leaving the character in same place? eg. Input=100,200,a,300 Output=300,200,a,100. I am using Arraylist which is String type.
String input = JOptionPane.showInputDialog("Enter a string:");
String[] abc = input.split(",");
ArrayList<String> num = new ArrayList<String>();
for (int i = 0; i < abc.length; i++)
{
num.add(abc[i]);
}
Collections.sort(num, Collections.reverseOrder());
System.out.println(num);
One can use Collections.reverseOrder() comparator to sort the list in reverse order.
public class CollectionsDemo {
public static void main(String args[]) {
// create linked list object
LinkedList list = new LinkedList();
// populate the list
list.add(-28);
list.add(20);
list.add(-12);
list.add(8);
// create comparator for reverse order
Comparator cmp = Collections.reverseOrder();
// sort the list
Collections.sort(list, cmp);
System.out.println("List sorted in ReverseOrder: ");
for(int i : list){
System.out.println(i+ " ");
}
}
}
You may try to create your own comparator like this:
static <K,V extends Comparable<? super V>>
List<Entry<K, V>> reverseSortValues(Map<K,V> map)
{
List<Entry<K,V>> lst = new ArrayList<Entry<K,V>>(map.entrySet());
Collections.sort(lst,
new Comparator<Entry<K,V>>()
{
@Override
public int compare(Entry<K,V> e1, Entry<K,V> e2)
{
return e2.getValue().compareTo(e1.getValue());
}
}
);
return lst;
}
Create comparator for reverse order -
Comparator cmp = Collections.reverseOrder();
Then sort the list -
Collections.sort(num, cmp);
The Collections.reverseOrder() is used to get a Comparator that reverses the natural ordering.
Collections.sort()for that.