TreeMap with Looping
We can iterate TreeMap using enhanced for loop with keyset() method or by using enhanced for loop with EntrySet method or by using iterator
Case 1
Enhanced for loop with keyset()
Example
- import java.util.*;
- public class TreeMapEnhancedForLoopExample {
- public static void main(String args[]) {
- TreeMap<Integer,String> tm = new TreeMap<>();
- tm.put(3, “Three”);
- tm.put(1, “One”);
- tm.put(2, “Two”);
- Set<Integer> keys = tm.keySet();
- for(Integer key: keys){
- System.out.println(“Value of “+key+” is: “+tm.get(key));
- }
- }
- }
import java.util.*; public class TreeMapEnhancedForLoopExample { public static void main(String args[]) { TreeMap<Integer,String> tm = new TreeMap<>(); tm.put(3, “Three”); tm.put(1, “One”); tm.put(2, “Two”); Set<Integer> keys = tm.keySet(); for(Integer key: keys){ System.out.println(“Value of “+key+” is: “+tm.get(key)); } } }
In this program, We have accessed all the keys of TreeMap using keySet( ) method and then iterated all the keys using enhanced for loop and accessed value by passing key in each iteration in the loop.
Case 2
Enhanced for loop with entrySet()
Example
- import java.util.*;
- public class TreeMapEnhancedForLoopEntrySetExample {
- public static void main(String args[]) {
- TreeMap<Integer,String> tm = new TreeMap<>();
- tm.put(2, “Two”);
- tm.put(1, “One”);
- tm.put(3, “Three”);
- for (Map.Entry entry : tm.entrySet()) {
- Integer key = entry.getKey();
- Object value = entry.getValue();
- System.out.println(“Value of “+key+” is: “+value);
- }
- }
- }
import java.util.*; public class TreeMapEnhancedForLoopEntrySetExample { public static void main(String args[]) { TreeMap<Integer,String> tm = new TreeMap<>(); tm.put(2, “Two”); tm.put(1, “One”); tm.put(3, “Three”); for (Map.Entry entry : tm.entrySet()) { Integer key = entry.getKey(); Object value = entry.getValue(); System.out.println(“Value of “+key+” is: “+value); } } }
Case 3
Using iterator
Example
- import java.util.*;
- public class TreeMapIteratorExample {
- public static void main(String args[]) {
- TreeMap<Integer,String> tm = new TreeMap<>();
- tm.put(3, “Three”);
- tm.put(1, “One”);
- tm.put(2, “Two”);
- Iterator it = tm.entrySet().iterator();
- while (it.hasNext()) {
- Map.Entry pair = (Map.Entry)it.next();
- System.out.println(pair.getKey() + ” = ” + pair.getValue());
- }
- }
- }
import java.util.*; public class TreeMapIteratorExample { public static void main(String args[]) { TreeMap<Integer,String> tm = new TreeMap<>(); tm.put(3, “Three”); tm.put(1, “One”); tm.put(2, “Two”); Iterator it = tm.entrySet().iterator(); while (it.hasNext()) { Map.Entry pair = (Map.Entry)it.next(); System.out.println(pair.getKey() + ” = ” + pair.getValue()); } } }