arraylist<integer>
时间: 2023-04-24 21:01:00 浏览: 54
ArrayList<Integer> 是 Java 中的一种数据类型,表示一个动态数组,其中存储了多个整数。ArrayList 类是 Java 的一种集合类,支持动态增长,可以方便地存储、检索和删除数据。
相关问题
ArrayList<Integer>
An ArrayList is a class in Java that provides a dynamic array implementation. It is part of the Java Collections Framework and is used to store a collection of objects. The ArrayList class is a generic class that can be used to store objects of any type.
The ArrayList<Integer> denotes an ArrayList that can only store objects of the Integer type. This is achieved through the use of Java generics, which allows the type of objects stored in a collection to be specified at compile time.
Here's an example of how to create an ArrayList<Integer>:
```
ArrayList<Integer> myList = new ArrayList<Integer>();
```
This creates a new ArrayList that can store objects of the Integer type. The ArrayList is initially empty, and elements can be added using the `add()` method:
```
myList.add(1);
myList.add(2);
myList.add(3);
```
This adds the integers 1, 2, and 3 to the ArrayList. The `size()` method can be used to get the number of elements in the ArrayList:
```
int size = myList.size(); // size is now 3
```
Elements can be retrieved from the ArrayList using the `get()` method:
```
int element = myList.get(0); // element is now 1
```
This retrieves the first element in the ArrayList (at index 0) and stores it in the `element` variable.
ArrayList<Integer>的用法
ArrayList<Integer>是Java中的一个类,用于存储整数类型的动态数组。它可以动态地增加或减少数组的大小,而不需要手动进行内存管理。使用ArrayList<Integer>,可以方便地进行整数类型的存储和操作,例如添加、删除、查找等。以下是一个简单的示例代码:
ArrayList<Integer> list = new ArrayList<Integer>();
list.add(1);
list.add(2);
list.add(3);
System.out.println(list.get(0)); // 输出1
list.remove(1);
System.out.println(list.get(1)); // 输出3
这段代码创建了一个ArrayList<Integer>对象,向其中添加了三个整数1、2、3,并输出了第一个和第二个元素的值。然后,它删除了第二个元素,并再次输出了第二个元素的值。