Java ArrayList size()用法及代码示例

java.util.ArrayList类的size()方法用于获取此列表中的元素数。

用法:

public int size()

返回值：此方法返回此列表中的元素数。

以下示例说明了size()方法。

示例1:

// Java program to demonstrate 
// size() method 
// for Integer value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
        throws Exception 
    { 
        try { 
  
            // Creating object of ArrayList<Integer> 
            ArrayList<Integer> 
                arrlist = new ArrayList<Integer>(); 
  
            // Populating arrlist1 
            arrlist.add(1); 
            arrlist.add(2); 
            arrlist.add(3); 
            arrlist.add(4); 
            arrlist.add(5); 
  
            // print arrlist 
            System.out.println("Before operation: "
                               + arrlist); 
  
            // getting total size of arrlist 
            // using size() method 
            int size = arrlist.size(); 
  
            // print the size of arrlist 
            System.out.println("Size of list = "
                               + size); 
        } 
  
        catch (IndexOutOfBoundsException e) { 
  
            System.out.println("Exception thrown: "
                               + e); 
        } 
    } 
}

输出：

Before operation: [1, 2, 3, 4, 5]
Size of list = 5

示例2:

// Java program to demonstrate 
// size() method 
// for String value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
        throws Exception 
    { 
        try { 
  
            // Creating object of ArrayList<Integer> 
            ArrayList<String> 
                arrlist = new ArrayList<String>(); 
  
            // Populating arrlist1 
            arrlist.add("A"); 
            arrlist.add("B"); 
            arrlist.add("C"); 
  
            // print arrlist 
            System.out.println("Before operation: "
                               + arrlist); 
  
            // getting total size of arrlist 
            // using size() method 
            int size = arrlist.size(); 
  
            // print the size of arrlist 
            System.out.println("Size of list = "
                               + size); 
        } 
  
        catch (IndexOutOfBoundsException e) { 
  
            System.out.println("Exception thrown: "
                               + e); 
        } 
    } 
}

输出：

Before operation: [A, B, C]
Size of list = 3

相关用法

注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 ArrayList size() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。