Java TreeMap descendingMap()用法及代碼示例

descendingMap()方法用於返回此映射中包含的映射的逆序視圖。映射的倒序或降序是根據鍵的降序排列的。降序Map由該Map支持，因此對Map的更改會反映在降序Map中，反之亦然。

聲明語法：

public NavigableMap<K,V> descendingMap()

K:它是此映射維護的鍵的類型。
V:它是映射值的類型。

參數：無法使用

返回值：此Map的逆序或降序視圖。

範例1：

Java

// Java program to demonstrate descendingMap() method 
  
import java.util.*; 
  
public class Example1 { 
    public static void main(String[] args) 
    { 
  
        // Declaring the tree map of Integer and String 
        TreeMap<Integer, String> treemap 
            = new TreeMap<Integer, String>(); 
  
        // Add the mappings to the tree map using put() 
        treemap.put(2, "Two"); 
        treemap.put(16, "Sixteen"); 
        treemap.put(8, "Eight"); 
        treemap.put(6, "Six"); 
        treemap.put(10, "Ten"); 
  
        // store the descending order of mappings in dmap 
        NavigableMap dmap = treemap.descendingMap(); 
  
        System.out.println("Reverse navigable map values:"
                           + dmap); 
    } 
}

輸出

Reverse navigable map values:{16=Sixteen, 10=Ten, 8=Eight, 6=Six, 2=Two}

範例2：

Java

// Java Program to demonstrate descendingMap() method 
  
import java.util.*; 
  
public class Example2 { 
    public static void main(String[] args) 
    { 
  
        // Declaring the tree map of Integer and String 
        TreeMap<Integer, String> treemap 
            = new TreeMap<Integer, String>(); 
  
        // Add the mappings to the tree map using put() 
        treemap.put(11, "Abhishek Rout"); 
        treemap.put(9, "Akash Salvi"); 
        treemap.put(2, "Hemant Koul"); 
        treemap.put(8, "Vaibhav Kamble"); 
        treemap.put(6, "Sagar Joshi"); 
        treemap.put(10, "Onkar Dherange"); 
        treemap.put(7, "Rajwardhan Shinde"); 
        treemap.put(1, "Rahul Gavhane"); 
        treemap.put(4, "Abhishek Gadge"); 
        treemap.put(3, "Pratik Kulkarni"); 
        treemap.put(5, "Raviraj Bugge"); 
  
        // store the descending order of mappings in dmap 
        NavigableMap dmap = treemap.descendingMap(); 
  
        // print the mappings 
        System.out.println( 
            "List of students in reverse order:" + dmap); 
    } 
}

輸出

List of students in reverse order:{11=Abhishek Rout, 10=Onkar Dherange, 9=Akash Salvi, 8=Vaibhav Kamble, 7=Rajwardhan Shinde, 6=Sagar Joshi, 5=Raviraj Bugge, 4=Abhishek Gadge, 3=Pratik Kulkarni, 2=Hemant Koul, 1=Rahul Gavhane}

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注：本文由純淨天空篩選整理自antminer大神的英文原創作品 TreeMap descendingMap() Method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。