Java中的 ArrayList set() 方法及示例
Java.util.ArrayList类的set()方法用于将该列表中指定位置的元素替换为指定元素。
句法:
public E set(int index, E element)
参数:此方法将以下参数作为参数。
- index-要替换的元素的索引
- element-要存储在指定位置的元素
返回值:此方法返回先前在指定位置的元素。
异常:如果索引不在 ArrayList 的大小范围内,此方法将引发IndexOutOfBoundsException 。
下面是说明set()方法的示例。
示例 1:
// Java program to demonstrate
// set() method
// for Integer value
import java.util.*;
public class GFG1 {
public static void main(String[] argv) throws Exception
{
try {
// Creating object of ArrayList
ArrayList
arrlist = new ArrayList();
// 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);
// Replacing element at the index 3 with 30
// using method set()
int i = arrlist.set(3, 30);
// Print the modified arrlist
System.out.println("After operation: "
+ arrlist);
// Print the Replaced element
System.out.println("Replaced element: "
+ i);
}
catch (IndexOutOfBoundsException e) {
System.out.println("Exception thrown: "
+ e);
}
}
}
输出:
Before operation : [1, 2, 3, 4, 5]
After operation : [1, 2, 3, 30, 5]
Replaced element : 4
示例 2:对于IndexOutOfBoundsException
// Java program to demonstrate
// set() method
// for IndexOutOfBoundsException
import java.util.*;
public class GFG1 {
public static void main(String[] argv) throws Exception
{
try {
// Creating object of ArrayList
ArrayList
arrlist = new ArrayList();
// 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);
// Replacing element at the index 7 with 30
// using method set()
System.out.println("\nTrying to Replace"
+ " the element at"
+ " (index > Capacity) ");
int i = arrlist.set(7, 30);
// Print the modified arrlist
System.out.println("After operation: "
+ arrlist);
// Print the Replaced element
System.out.println("Replaced element: "
+ i);
}
catch (IndexOutOfBoundsException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
Before operation : [1, 2, 3, 4, 5]
Trying to Replace the element at (index > Capacity)
Exception thrown : java.lang.IndexOutOfBoundsException: Index: 7, Size: 5