print map using for each in java code example
Example 1: how to print the map in java
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.stream.Stream;
class MapUtil
{
// Program to print all keys present in the Map using keySet() in Java
public static void main (String[] args)
{
Map map = new HashMap<>();
map.put(1, "One");
map.put(2, "Two");
// 1. using Iterator
Iterator itr = map.keySet().iterator();
while (itr.hasNext()) {
System.out.println(itr.next());
}
// 2. For-each Loop
for (Integer key : map.keySet()) {
System.out.println(key);
}
// 3. Java 8 - Collection.iterator() + Iterator.forEachRemaining()
map.keySet().iterator()
.forEachRemaining(System.out::println);
// 4. Java 8 - Collection.stream() + Stream.forEach()
map.keySet().stream()
.forEach(System.out::println);
// Java 8 - Stream.of() + Collection.toArray() + Stream.forEach()
Stream.of(map.keySet().toArray())
.forEach(System.out::println);
// 5. Convert to String
System.out.println(map.keySet().toString());
// Java 8
Stream.of(map.keySet().toString())
.forEach(System.out::println);
}
}
Example 2: printing elemenst in hashmap
import java.util.HashMap;
import java.util.Map;
import java.util.Iterator;
import java.util.Set;
public class Details {
public static void main(String args[]) {
/* This is how to declare HashMap */
HashMap hmap = new HashMap();
/*Adding elements to HashMap*/
hmap.put(12, "Chaitanya");
hmap.put(2, "Rahul");
hmap.put(7, "Singh");
hmap.put(49, "Ajeet");
hmap.put(3, "Anuj");
/* Display content using Iterator*/
Set set = hmap.entrySet();
Iterator iterator = set.iterator();
while(iterator.hasNext()) {
Map.Entry mentry = (Map.Entry)iterator.next();
System.out.print("key is: "+ mentry.getKey() + " & Value is: ");
System.out.println(mentry.getValue());
}
/* Get values based on key*/
String var= hmap.get(2);
System.out.println("Value at index 2 is: "+var);
/* Remove values based on key*/
hmap.remove(3);
System.out.println("Map key and values after removal:");
Set set2 = hmap.entrySet();
Iterator iterator2 = set2.iterator();
while(iterator2.hasNext()) {
Map.Entry mentry2 = (Map.Entry)iterator2.next();
System.out.print("Key is: "+mentry2.getKey() + " & Value is: ");
System.out.println(mentry2.getValue());
}
}
}