在哈希表中使用枚举读取元素的 Java 程序
原文:https://www . geesforgeks . org/Java-程序-读取-元素-使用-枚举-在-哈希表/
java 中的枚举 是预定义的接口之一,其对象用于从集合框架变量(如堆栈、向量、哈希表等)中检索数据。)仅在向前的方向,而不在向后的方向。
哈希表是一个类哈希表类实现了一个映射,将键映射到值。它将键/值对存储在哈希表中。在这个数据结构中,我们指定了一个用作键的对象,以及我们想要与该键关联的值。然后对该键进行哈希运算,得到的哈希代码用作该值在表中存储的索引。哈希表不提供任何枚举,而哈希表不提供快速枚举。哈希表的层次结构如下:
语法:
public class Hashtable<K,V> extends Dictionary<K,V> implements Map<K,V>, Cloneable, Serializable
参数:
- 克:钥匙插入。
- v:分配给键的值。
为了创建哈希表,从 java.util.Hashtable 中导入哈希表,其中,K、V 是整数、字符串、浮点数等数据类型。
语法:创建哈希表
Hashtable<K, V> ht = new Hashtable<K, V>();
实施:大学生信息
例
Java 语言(一种计算机语言,尤用于创建网站)
// Java Program to read elements
// using enumeration in hashtable
// Importing enumeration class
import java.util.Enumeration;
// Importing hash table
import java.util.Hashtable;
// Class
public class GFG {
// Main driver method
public static void main(String a[])
{
// Creating hash table
Hashtable<String, String> hm
= new Hashtable<String, String>();
// Add key-value pair to Hashtable
// Custom inputs
hm.put("Name", "Bahubali");
hm.put("College", "Amarnath");
hm.put("Department", "Vedics");
// enum
Enumeration<String> keys = hm.keys();
// Condition check whether element(K,V) is present
// using hasMoreElements()
while (keys.hasMoreElements()) {
String key = keys.nextElement();
// Print corresponding key-value pair
System.out.println("Value of " + key
+ " is: " + hm.get(key));
}
System.out.println();
// Creating a new Hashtable
Hashtable<String, String> hm1
= new Hashtable<String, String>();
// Adding key-value pair to Hashtable
// Custom inputs
hm1.put("Name", "Ravaan");
hm1.put("College", "SriLanka");
hm1.put("Department", "CS");
// Enum
Enumeration<String> keys1 = hm1.keys();
// Condition check whether element(K,V) is present
// using hasMoreElements()
while (keys1.hasMoreElements()) {
String key = keys1.nextElement();
// Print corresponding key-value pair
System.out.println("Value of " + key
+ " is: " + hm1.get(key));
}
System.out.println();
// Creating a new Hashtable
Hashtable<String, String> hm2
= new Hashtable<String, String>();
// Adding key-value pair to Hashtable
// Custom inputs
hm2.put("Name", "Kattappa");
hm2.put("College", "Beardo");
hm2.put("Department", "War");
/// enum
Enumeration<String> keys2 = hm2.keys();
// Condition check whether element(K,V) is present
// using hasMoreElements()
while (keys2.hasMoreElements()) {
String key = keys2.nextElement();
// Print corresponding key-value pair
System.out.println("Value of " + key
+ " is: " + hm2.get(key));
}
}
}
Output
Value of Name is: Bahubali
Value of College is: Amarnath
Value of Department is: Vedics
Value of Name is: Ravaan
Value of College is: SriLanka
Value of Department is: CS
Value of Name is: Kattappa
Value of College is: Beardo
Value of Department is: War
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