How do you loop a value in a map?

How do you loop a value in a map?

1. Using a for loop to iterate through a HashMap

1. // importing library.
2. import java. util. HashMap;
3. import java. util. Map;
4. ​
5. // class for iterating HashMap.
6. public class Iterate {
7. public static void main(String[] arguments) {
8. // creating HashMap.

How do I iterate a map using keySet?

Iterate Map in Java using keySet() method

1. Iterator itr = map. keySet(). iterator();
2. while (itr. hasNext())
3. K key = itr. next();
4. V value = map. get(key);
5. System. out. println(key + “=” + value);

Is there a way to iterate over a map?

There are several ways to iterate over map. Here is comparison of their performances for a common data set stored in map by storing a million key value pairs in map and will iterate over map. for (Map.Entry entry : testMap.entrySet ()) { entry.getKey (); entry.getValue (); }

How to iterate over a set of keys in Java?

Iterating over keys or values using keySet () and values () methods. Map.keySet () method returns a Set view of the keys contained in this map and Map.values () method returns a collection-view of the values contained in this map. So If you need only keys or values from the map, you can iterate over keySet or values using for-each loops.

What’s the difference between an iterator and a map in Java?

A map is not a Collection but still, consider under the Collections framework. Hence, a Map is an interface which does not extend the Collections interface. An iterator is an interface used for iterate over a collection. It takes the place of Enumeration in Java Collections Framework. The difference between iterator and Enumeration is:

How to iterate through a hashmap in Java?

I’ve presumed you want to call .remove () on the child map, which will lead to a ConcurrentModificationException if done while looping the entrySet – it looks as though you discovered this already. I’ve also swapped out your use of casting with strongly-typed generics as suggested in the comments.