如何在 Java 中查找ArrayList的长度

通过使用ArrayList size() ArrayList类的方法，我们可以很容易地确定ArrayList的大小。此方法返回ArrayList的元素数。

public int size()

示例：

package beginnersbook.com;
import java.util.ArrayList;
public class Details
{
    public static void main(String [] args)
    {
        ArrayList<Integer> al=new ArrayList<Integer>();
        System.out.println("Initial size: "+al.size());
        al.add(1);
        al.add(13);
        al.add(45);
        al.add(44);
        al.add(99);
        System.out.println("Size after few additions: "+al.size());
        al.remove(1);
        al.remove(2);
        System.out.println("Size after remove operations: "+al.size());
        System.out.println("Final ArrayList: ");
        for(int num: al){
            System.out.println(num);
        }
   }
}

输出：

Initial size: 0
Size after few additions: 5
Size after remove operations: 3
Final ArrayList: 
1
45
99