java enummap

EnumMap类的size()方法 (EnumMap Class size() method)

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

  size()方法在java.util包中可用。

• size() method is used to return the size of this enum map (i.e. it returns the number of key-value pairs exists in this enum map).

  size()方法用于返回此枚举映射的大小(即，它返回此枚举映射中存在的键值对的数量)。

• size() 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.

  size()方法是一种非静态方法，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。

• size() method does not throw an exception at the time of returning the size of this map.

  返回此地图的大小时， size()方法不会引发异常。

Syntax:

句法：

public int size();

Parameter(s):

参数：

• It does not accept any parameter.

  它不接受任何参数。

Return value:

返回值：

The return type of this method is int, it returns the number of key-value mappings exists in this enum map.

此方法的返回类型为int ，它返回此枚举映射中存在的键值映射数。

Example:

例：

// Java program to demonstrate the example // of int size() method of EnumMapimport java.util.*;public class SizeOfEnumMap {
       public enum Colors {
           RED,        BLUE,        PINK,        YELLOW    };    public static void main(String[] args) {
           // We are creating EnumMap object        EnumMap < Colors, String > em =            new EnumMap < Colors, String > (Colors.class);        // By using put() method is to        // add the linked values in an        // EnumMap (em)        em.put(Colors.RED, "1");        em.put(Colors.BLUE, "2");        em.put(Colors.PINK, "3");        em.put(Colors.YELLOW, "4");        // Display EnumMap        System.out.println("EnumMap (em) :" + em);        // By using size() method isto        // return the number of key-value        // pairs exists in an EnumMap        int size = em.size();        // Display Size Of An EnumMap        System.out.println("em.size(): " + size);    }}

Output

输出量

EnumMap (em) :{RED=1, BLUE=2, PINK=3, YELLOW=4}em.size(): 4

翻译自:

java enummap