LinkedHashMap is a pre-defined class in java like HashMap. The only difference between LinkedHashMap and HashMap is LinkedHashMap preserve insertion order while HashMap does not preserve insertion order. The task is to iterate through a LinkedHashMap using an Iterator. We use the Iterator object to iterate through a LinkedHashMap.
Example
Input: Key - 2 : Value - 6 Key - 3 : Value - 4 Key - 6 : Value - 5 Key - 4 : Value - 10 Key - 5 : Value - 6 Output: Key = Value 2 = 6 3 = 4 6 = 5 4 = 10 5 = 6
Algorithm :
1. Create a LinkedHashMap and add key, value pairs.
2. we convert our LinkedHashMap to entrySet using,
Set s = lhm.entrySet();
3. we define iterator for our set.
Iterator it=s.iterator();
4. Using while loop we iterate through our linkedHashMap.
while(it.hasNext()) System.out.println(it.next());
Implementation
// Java program to Iterate through LinkedHashMap using an // Iterator import java.io.*;
import java.util.*;
class GFG {
public static void main(String[] args)
{
// create a linkedhashmap
LinkedHashMap<Integer, Integer> lhm
= new LinkedHashMap<>();
// add mappings
lhm.put( 2 , 6 );
lhm.put( 3 , 4 );
lhm.put( 6 , 8 );
lhm.put( 4 , 10 );
lhm.put( 5 , 6 );
// create an entryset
Set s = lhm.entrySet();
// create an iterator
Iterator it = s.iterator();
// iterate an print the mappings
System.out.println( "key=Value" );
while (it.hasNext()) {
System.out.println(it.next());
}
}
} |
key=Value 2=6 3=4 6=8 4=10 5=6
Time Complexity: O(n).