Question

How to get the keys of LinkedHashMap in Java

Answer 1

import java.util.LinkedHashMap;
import java.util.Set;
 
public class MyClass {
    public static void main(String[] args) {
        LinkedHashMap<Integer, String> lhmap = new LinkedHashMap<Integer, String>();
        
        lhmap.put(1, "java");
        lhmap.put(2, "c++");
        lhmap.put(3, "c#");
        lhmap.put(4, "python");
        lhmap.put(5, "c");
        
        Set<Integer> keys = lhmap.keySet();
        
        System.out.println(keys);
        
    }
}
 
 
 
/*
run:
 
[1, 2, 3, 4, 5]
 
*/

 

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Answer 2

import java.util.LinkedHashMap;
import java.util.Iterator;
import java.util.Set;
 
public class MyClass {
    public static void main(String[] args) {
        LinkedHashMap<Integer, String> lhmap = new LinkedHashMap<Integer, String>();
        
        lhmap.put(1, "java");
        lhmap.put(2, "c++");
        lhmap.put(3, "c#");
        lhmap.put(4, "python");
        lhmap.put(5, "c");
        
        Set<Integer> keys = lhmap.keySet();
        
        Iterator<Integer> iterator = keys.iterator();
        
        while( iterator.hasNext() ){
            System.out.println( iterator.next() );
        }
    }
}
 
 
 
/*
run:
 
1
2
3
4
5

*/

 

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