用示例列出 Java 中的 size()方法
原文:https://www . geesforgeks . org/list-size-method-in-Java-with-examples/
Java 中列表界面的 size() 方法用于获取该列表中的元素个数。也就是说，此方法返回此列表容器中存在的元素的计数。
语法:
public int size()
参数:该方法不取任何参数。
返回值:该方法返回该列表中元素个数。
说明:假设它是一个整数列表
Input : {3,2,1,5,7}
Output : 5
例 1:
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to Illustrate size() method
// of List class for Integer value
// Importing required classes
import java.util.*;
// Main class
public class GFG {
// Main driver method
public static void main(String[] arg)
{
// Creating object of ArrayList class
List<Integer> list = new ArrayList<Integer>();
// Populating List by adding integer elements
// using add() method
list.add(1);
list.add(2);
list.add(3);
list.add(4);
list.add(5);
// Printing elements of List
System.out.println("Before operation: " + list);
// Getting total size of list
// using size() method
int size = list.size();
// Printing the size of List
System.out.println("Size of list = " + size);
}
}
Output
Before operation: [1, 2, 3, 4, 5]
Size of list = 5
例 2:
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to Illustrate size() method
// of List class for Integer value
// Importing required classes
import java.util.*;
// Main class
public class GFG {
// Main driver method
public static void main(String[] args)
{
// Creating an empty string list by
// declaring elements of string type
List<String> list = new ArrayList<String>();
// Populating List by adding string elements
// using add() method
list.add("Geeks");
list.add("for");
list.add("Geeks");
// Printing the List
System.out.println("Before operation: " + list);
// Getting total size of list
// using size() method
int size = list.size();
// Printing the size of list
System.out.println("Size of list = " + size);
}
}
Output
Before operation: [Geeks, for, Geeks]
Size of list = 3
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