Java和Collection之间有什么区别？ [英] What is the difference between Collection and List in Java?

问题描述

Collection和List在Java中有什么区别？

解决方案

首先：a 列表 是一个 集合 。 $ >只是：一个项目的集合。

A 列表您可以添加内容，删除内容，将有关定义的填充序列的信息添加到其中：您可以获取位置 n 的元素，您可以在位置 n 添加元素，您可以删除元素

在集合中，您不能这样做：

还有其他专门的集合，例如 设置 这增加了它将不会包含相同元素两次的特征。

What is the difference between Collection and List in Java? When and which I should use?

解决方案

First off: a List is a Collection. It is a specialized Collection, however.

A Collection is just that: a collection of items. You can add stuff, remove stuff, iterate over stuff and query how much stuff is in there.

A List adds the information about a defined sequence of stuff to it: You can get the element at position n, you can add an element at position n, you can remove the element at position n.

In a Collection you can't do that: "the 5th element in this collection" isn't defined, because there is no defined order.

There are other specialized Collections as well, for example a Set which adds the feature that it will never contain the same element twice.

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