Store in Java 2D map and turn with for statement

** 1, the information "student name, subject name / score" has been made into a two-dimensional map data structure. ** ** ** 2, the total score and average score of each student were output using the for statement. ** **

Collection classes cannot store anything that is not an instance. However, it can be stored by converting int type information to Integer type (wrapper class).

Run in Eclipse Oxygen

A program that creates and turns a 2D map

import java.util.LinkedHashMap;
import java.util.Map;

public class MapScore {

	public static void main(String[] args) {
		//Create a 2D map
		//Immediately before the map name, that is, Map<String, Map<String, Integer>>Up to data type
		Map<String, Map<String, Integer>> nameMap = new LinkedHashMap<String, Map<String, Integer>>();

		//Suzuki
		Map<String, Integer> scoresMap_suzuki = new LinkedHashMap<String,  Integer>();
		scoresMap_suzuki.put("National language", 78);
		scoresMap_suzuki.put("Math", 90);
		scoresMap_suzuki.put("English", 20);

		//Mr Sato
		Map<String, Integer> scoresMap_satoh = new LinkedHashMap<String,  Integer>();
		scoresMap_satoh.put("National language", 50);
		scoresMap_satoh.put("Math", 40);
		scoresMap_satoh.put("English", 90);

		//Tanaka
		Map<String, Integer> scoresMap_tanaka = new LinkedHashMap<String,  Integer>();
		scoresMap_tanaka.put("National language", 80);
		scoresMap_tanaka.put("Math", 60);
		scoresMap_tanaka.put("English", 85);

		//Realize a 2D map by putting the above 3 maps in the value of the name map
		nameMap.put("Suzuki", scoresMap_suzuki);
		nameMap.put("Sato", scoresMap_satoh);
		nameMap.put("Tanaka", scoresMap_tanaka);

		//Turn the name map with Extended for
		//In the case of LinkedHashMap, it is fetched in the order of storage.
		for (Map.Entry<String,  Map<String, Integer>> element : nameMap.entrySet()) {

			//Get the value of nameMap and assign it to a new map
			Map<String,Integer> scores = element.getValue();

			int sum = 0;
			int avg = 0;

			//scoresMap_Turn the value of the name, that is, the score, and substitute it for sum
			for(int hogeInt : scores.values()){
				sum += hogeInt;
				avg  = sum  / scores.size();
			}

			//For the number of people((For 3 people) Output
			System.out.println(element + "The total score is" + sum + " " + "The average is" + avg);
		}
	}
}

Execution result

Execution result

Suzuki={National language=78,Math=90,English=20}The total score is 188 and the average is 62
Sato={National language=50,Math=40,English=90}Total score is 180 Average is 60
Tanaka={National language=80,Math=60,English=85}Total score is 225 Average is 75