java treemap
TreeMap類的size()方法 (TreeMap 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 TreeMap or in other words, we can say it returns the number of key-value pairs that exist in this TreeMap.
size()方法用于返回此TreeMap的大小，換句話說，我們可以說它返回此TreeMap中存在的鍵/值對的數量。
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()方法是一種非靜態方法，只能通過類對象訪問，如果嘗試使用類名稱訪問該方法，則會收到錯誤消息。
size() method does not throw an exception at the time of returning size.
返回size時， size()方法不會引發異常。
Syntax:
句法：
public int size();
Parameter(s):
參數：
It does not accept any parameter.
它不接受任何參數。
Return value:
返回值：
The return type of the method is int, it returns the number of existing key-value pairs in this TreeMap.
方法的返回類型為int ，它返回此TreeMap中現有的鍵值對的數量。
Example:
例：
// Java program to demonstrate the example
// of int size() method of TreeMap
import java.util.*;
public class SizeOfTreeMap {
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 size() method is to
// return the size of this TreeMap
int size = tm.size();
// Display size of TreeMap tm
System.out.println("tm.size(): " + size);
}
}
Output
輸出量
tm: {1=C, 2=Php, 3=Java, 4=C++}
tm.size(): 4
翻譯自: https://www.includehelp.com/java/treemap-size-method-with-example.aspx
java treemap
