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法律研究Java 程式迭代一個 HashMap
在本文中，我們將瞭解如何迭代一個 HashMap。Java HashMap 是基於雜湊表的 Java Map 介面的實現。它是一個鍵值對集合。
以下是它的演示示例 −
假設我們的輸入是 −
Input Hashmap: {Java=Enterprise, JavaScript=Frontend, Mysql=Backend, Python=ML/AI}期望的輸出是 −
The keys of the Hashmap are: Java, JavaScript, Mysql, Python, The Values of the Hashmap are: Enterprise, Frontend, Backend, ML/AI,
演算法
Step 1 - START Step 2 - Declare namely Step 3 - Define the values. Step 4 - Create a hashmap of strings and initialize elements in it using the ‘put’ method. Step 5 - Display the hashmap on the console. Step 6 - Iterate over the elements of the hashmap, and fetch each key using ‘keySet’ method. Step 7 - Display this on the console. Step 6 - Stop
示例 1
在此，我們在“main”函式下將所有操作繫結在一起。
import java.util.HashMap;
import java.util.Map.Entry;
public class Demo {
public static void main(String[] args) {
System.out.println("The required packages have been imported");
HashMap<String, String> input_map = new HashMap<>();
input_map.put("Java", "Enterprise");
input_map.put("Python", "ML/AI");
input_map.put("JavaScript", "Frontend");
input_map.put("Mysql", "Backend");
System.out.println("The HashMap is defined as: " + input_map);
System.out.print("\nThe keys of the Hashmap are: ");
for(String key: input_map.keySet()) {
System.out.print(key);
System.out.print(", ");
}
System.out.print("\nThe Values of the Hashmap are: ");
for(String value: input_map.values()) {
System.out.print(value);
System.out.print(", ");
}
}
}輸出
The required packages have been imported
The HashMap is defined as: {Java=Enterprise, JavaScript=Frontend, Mysql=Backend, Python=ML/AI}
The keys of the Hashmap are: Java, JavaScript, Mysql, Python,
The Values of the Hashmap are: Enterprise, Frontend, Backend, ML/AI,示例 2
在此，我們將操作封裝到函式中，展示面向物件程式設計。
import java.util.HashMap;
public class Demo {
static void print_keys(HashMap<String, String> input_map){
System.out.print("\nThe keys of the Hashmap are: ");
for(String key: input_map.keySet()) {
System.out.print(key);
System.out.print(", ");
}
}
static void print_values( HashMap<String, String> input_map){
System.out.print("\nThe Values of the Hashmap are: ");
for(String value: input_map.values()) {
System.out.print(value);
System.out.print(", ");
}
}
public static void main(String[] args) {
System.out.println("The required packages have been imported");
HashMap<String, String> input_map = new HashMap<>();
input_map.put("Java", "Enterprise");
input_map.put("Python", "ML/AI");
input_map.put("JavaScript", "Frontend");
input_map.put("Mysql", "Backend");
System.out.println("The HashMap is defined as: " + input_map);
print_keys(input_map);
print_values(input_map);
}
}輸出
The required packages have been imported
The HashMap is defined as: {Java=Enterprise, JavaScript=Frontend, Mysql=Backend, Python=ML/AI}
The keys of the Hashmap are: Java, JavaScript, Mysql, Python,
The Values of the Hashmap are: Enterprise, Frontend, Backend, ML/AI,
更新於: 2022-3-30
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