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How to iterate LinkedHashMap in Java?

Last Updated : 25 Apr, 2023
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LinkedHashMap class extends HashMap and maintains a linked list of the entries in the map, in the order in which they were inserted. This allows insertion-order iteration over the map. That is, when iterating a LinkedHashMap, the elements will be returned in the order in which they were inserted.

There are basically two ways to iterate over LinkedHashMap:

  1. Using keySet() and get() Method
  2. Using entrySet() and Iterator

Method 1: Iterating LinkedHashMap using keySet() and get() Method

Syntax:

linked_hash_map.keySet()

Parameters: The method does not take any parameter.

Return Value: The method returns a set having the keys of the LinkedHashMap.

  • Through keySet() method we will obtain a set having keys of the map.
  • And then after running a loop over this set, we can obtain each key and its value using get() method.

Java




// Java Program to iterate through LinkedHashMap using
// keySet() and get() Method
 
import java.util.LinkedHashMap;
import java.util.Set;
 
public class GFG {
 
    public static void main(String a[])
    {
        // making the object of LinkedHashMap
        LinkedHashMap<String, String> linkedHashMap
                 = new LinkedHashMap<String, String>();
       
        // adding the elements in linkedHashMap
        linkedHashMap.put("One", "First element");
        linkedHashMap.put("Two", "Second element");
        linkedHashMap.put("Three", "Third element");
 
        Set<String> keys = linkedHashMap.keySet();
       
        // printing the elements of LinkedHashMap
        for (String key : keys) {
            System.out.println(key + " -- "
                               + linkedHashMap.get(key));
        }
       
    }
}
 






                        










Output


One -- First element
Two -- Second element
Three -- Third element




Method 2: Iterating LinkedHashMap using entrySet() and Iterator


Syntax:


Linkedhash_map.entrySet()


Parameters: The method does not take any parameter.


Return Value: The method returns a set having same elements as the LinkedHashMap.




Java














                                    




                                    

                                    




                                    




                                    

                                    

                                    
                                




















// Java Program to iterate over linkedHashMap using


// entrySet() and iterator


 


import java.util.Iterator;


import java.util.LinkedHashMap;


import java.util.Set;


 


public class GFG {


 


    public static void main(String[] args)


    {


 


        // Create a LinkedHashMap and populate it with


        // elements


        LinkedHashMap<String, String> linkedHashMap


            = new LinkedHashMap<String, String>();


 


        // adding the elements to the linkedHashMap


        linkedHashMap.put("One", "First element");


        linkedHashMap.put("Two", "Second element");


        linkedHashMap.put("Three", "Third element");


 


        // Get a set of all the entries (key - value pairs)


        // contained in the LinkedHashMap


        Set entrySet = linkedHashMap.entrySet();


 


        // Obtain an Iterator for the entries Set


        Iterator it = entrySet.iterator();


 


        // Iterate through LinkedHashMap entries


        System.out.println("LinkedHashMap entries : ");


 


        while (it.hasNext())


            // iterating over each element using it.next()


            // method


            System.out.println(it.next());


    }


}



















                        







                        










Output


LinkedHashMap entries : 
One=First element
Two=Second element
Three=Third element






                                    


                                                                        

                                        

                                            

                                                

                                                    
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                                                    lavishgarg26                                                

                                            

                                            

            
                                        

                                        

                                            
    

        
        
    
                                            

                                                
                                                
                                            

                                            

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