Java 中的 set(int, obj o) 方法有什么作用?


ArrayList 类的 set() 方法使用指定的元素替换该列表中指定位置处的元素。

示例

import java.util.ArrayList;

public class Sample {
   public static void main(String args[]) {
      ArrayList al = new ArrayList();
      System.out.println("Initial size of al: " + al.size());
      al.add("C");
      al.add("A");
      al.add("E");
      al.add(1, "A2");
      System.out.println("Size of al after additions: " + al.size());
      System.out.println("Contents of al: " + al);
      System.out.println("Size of al after deletions: " + al.size());
      System.out.println("Contents of al: " + al);
      al.set(2, "new");
      System.out.println("Contents of al after setting the element: " + al);
   }
}

输出

Initial size of al: 0
Size of al after additions: 4
Contents of al: [C, A2, A, E]
Size of al after deletions: 4
Contents of al: [C, A2, A, E]
Contents of al after setting the element: [C, A2, new, E]

更新于: 20-Feb-2020

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