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Create a TreeMap in Java and add key-value pairs
A TreeMap cannot contain duplicate keys. TreeMap cannot contain the null key. However, It can have null values.
Let us first see how to create a TreeMap −
TreeMap<Integer,String> m = new TreeMap<Integer,String>();
Add some elements in the form of key-value pairs −
m.put(1,"India"); m.put(2,"US"); m.put(3,"Australia"); m.put(4,"Netherlands"); m.put(5,"Canada");
The following is an example to create a TreeMap and add key-value pairs −
Example
import java.util.*;
public class Demo {
public static void main(String args[]) {
TreeMap<Integer,String> m = new TreeMap<Integer,String>();
m.put(1,"India");
m.put(2,"US");
m.put(3,"Australia");
m.put(4,"Netherlands");
m.put(5,"Canada");
for(Map.Entry e:m.entrySet()) {
System.out.println(e.getKey()+" "+e.getValue());
}
}
}Output
1 India 2 US 3 Australia 4 Netherlands 5 Canada
Updated on: 30-Jul-2019
1K+ Views
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