java treemap

TreeMap类lastKey()方法 (TreeMap Class lastKey() method)

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

  lastKey()方法在java.util包中可用。

• lastKey() method is used to return the last highest key element value exists in this TreeMap.

  lastKey()方法用于返回此TreeMap中存在的最后一个最高键元素值。

• lastKey() 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.

  lastKey()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。

• lastKey() method may throw an exception at the time of returning the last highest key-value element.

  返回最后一个最高键值元素时， lastKey()方法可能会引发异常。

  NoSuchElementException: This exception may throw when this TreeMap is blank.

  NoSuchElementException ：如果此TreeMap为空白，则可能引发此异常。

Syntax:

句法：

    public Key lastKey();

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 the method is Key, it retrieves the last higest key element exists in this TreeMap.

方法的返回类型为Key ，它检索此TreeMap中存在的最后一个higest key元素。

Example:

例：

// Java program to demonstrate the example 
// of Key lastKey() method of TreeMap 
import java.util.*;
public class LastKeyOfTreeMap {
public static void main(String[] args) {
// Instantiates TreeMap
TreeMap < Integer, String > tm = new TreeMap < Integer, String > ();
// By using put() method is
// to put the key-value pairs in
// treemap tm
tm.put(1, "C");
tm.put(4, "C++");
tm.put(3, "Java");
tm.put(2, "Php");
// Display TreeMap tm
System.out.println("tm: " + tm);
// By using lastKey() method is
// used to return the key element
// linked with the largest key element 
// value i.e. 4
// Display Returned Key Element
System.out.println("tm.lastKey(): " + tm.lastKey());
}
}

Output

输出量

tm: {1=C, 2=Php, 3=Java, 4=C++}
tm.lastKey(): 4

翻译自: https://www.includehelp.com/java/treemap-lastkey-method-with-example.aspx

java treemap