hashmap put方法

HashMap类的put()方法 (HashMap Class put() method)

• put() method is available in java.util package.

  put()方法在java.util包中可用。

• put() method is used to link the given value element with the given key element in this HashMap.

  put()方法用于在此HashMap中链接给定值元素和给定键元素。

• put() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  put()方法是一个非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。

• put() method does not throw an exception at the time of replacing the old element if exists.

  put()方法在替换旧元素(如果存在)时不会引发异常。

Syntax:

句法：

public Value put(Key key_ele, Value val_ele);

Parameter(s):

参数：

• Key key_ele – represents the key element with which the given value element is to be linked.

  Key key_ele –表示与给定值元素链接的键元素。

• Value val_ele – represents the value element with which the given key element is to be linked.

  值val_ele –表示将与给定键元素链接的value元素。

Return value:

返回值：

The return type of the method is Value, it returns the old element linked with the given key element when exists otherwise it returns null.

该方法的返回类型为Value ，如果存在则返回与给定键元素链接的旧元素，否则返回null。

Example:

例：

// Java program to demonstrate the example // of Value put(Key key_ele, Value val_ele)// method of HashMap import java.util.*;public class PutOfHashMap {
       public static void main(String[] args) {
           // Instantiates a HashMap object        Map < Integer, String > map = new HashMap < Integer, String > ();        // By using put() method is to add        // key-value pairs in a HashMap        map.put(10, "C");        map.put(20, "C++");        map.put(50, "JAVA");        map.put(40, "PHP");        map.put(30, "SFDC");        // Display HashMap        System.out.println("HashMap: " + map);        // By using put() method is to        // replace the existing value associated        // for the given key element with the        // new value element        map.put(50, "Microservices");        // Display Modified HashMap        System.out.print("HashMap: " + map);    }}

Output

输出量

HashMap: {50=JAVA, 20=C++, 40=PHP, 10=C, 30=SFDC}HashMap: {50=Microservices, 20=C++, 40=PHP, 10=C, 30=SFDC}

翻译自:

hashmap put方法