52 lines
1.6 KiB
Java
52 lines
1.6 KiB
Java
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/*
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* File: hash_map.java
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* Created Time: 2022-12-04
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* Author: Krahets (krahets@163.com)
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*/
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package chapter_hashing;
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import java.util.*;
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import include.*;
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public class hash_map {
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public static void main(String[] args) {
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/* 初始化哈希表 */
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Map<Integer, String> map = new HashMap<>();
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/* 添加操作 */
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// 在哈希表中添加键值对 (key, value)
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map.put(10001, "小哈");
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map.put(10002, "小啰");
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map.put(10003, "小算");
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map.put(10004, "小法");
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map.put(10005, "小哇");
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System.out.println("\n添加完成后，哈希表为\nKey -> Value");
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PrintUtil.printHashMap(map);
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/* 查询操作 */
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// 向哈希表输入键 key ，得到值 value
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String name = map.get(10002);
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System.out.println("\n输入学号 10002 ，查询到姓名 " + name);
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/* 删除操作 */
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// 在哈希表中删除键值对 (key, value)
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map.remove(10005);
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System.out.println("\n删除 10005 后，哈希表为\nKey -> Value");
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PrintUtil.printHashMap(map);
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/* 遍历哈希表 */
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System.out.println("\n遍历键值对 Key->Value");
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for (Map.Entry <Integer, String> kv: map.entrySet()) {
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System.out.println(kv.getKey() + " -> " + kv.getValue());
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}
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System.out.println("\n单独遍历键 Key");
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for (int key: map.keySet()) {
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System.out.println(key);
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}
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System.out.println("\n单独遍历值 Value");
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for (String val: map.values()) {
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System.out.println(val);
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}
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}
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}
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