Java: Get the portion of a map whose keys range from a given key to another key

Last update on May 23 2025 13:08:43 (UTC/GMT +8 hours)

21. Get SubMap from Key to Exclusive Key

Write a Java program to get the portion of a map whose keys range from a given key (inclusive) to another key (exclusive).

Sample Solution:-

Java Code:

import java.util.*;
import java.util.Map.Entry;  
public class Example21 {  
          public static void main(String args[]) {

  // Declare tree maps
  TreeMap < Integer, String > tree_map = new TreeMap < Integer, String > ();
  SortedMap < Integer, String > sub_tree_map = new TreeMap < Integer, String > ();

  // Put elements to the map 
  tree_map.put(10, "Red");
  tree_map.put(20, "Green");
  tree_map.put(30, "Black");
  tree_map.put(40, "White");
  tree_map.put(50, "Pink");
  System.out.println("Orginal TreeMap content: " + tree_map);
  sub_tree_map = tree_map.subMap(20, 40);
  System.out.println("Sub map key-values: " + sub_tree_map);
 }
}

Sample Output:

Orginal TreeMap content: {10=Red, 20=Green, 30=Black, 40=White, 50=Pink
}                                                                      
Sub map key-values: {20=Green, 30=Black}

For more Practice: Solve these Related Problems:

Write a Java program to use subMap() on a TreeMap to extract a sub-map with keys in the range [key1, key2) and print it.
Write a Java program to iterate over a sub-map obtained with subMap() and compute the sum of its values.
Write a Java program to filter a TreeMap’s entries using Java streams to collect those with keys in a specified range.
Write a Java program to compare a sub-map obtained via subMap() with manually filtered entries from the original TreeMap.

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Java Code Editor:

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