size()如何在Java的ArrayList类中工作? [英] How does size( ) works in java's ArrayList class?

问题描述

因此，为了获得最高效的代码，我真的很想知道Java ArrayList中的size()方法是如何工作的……它像每个简单的对象一样，对所有元素进行遍历所有位置吗列表?还是只是通过注册的最后一个索引获取大小?

So, in order to get the most efficient code, I really wanted to know how does the size() method in Java ArrayList work... Does it count every element, going through all the positions, like a simple list? or does it just gets the size by the last index registered?

提前谢谢！

推荐答案

查看它返回一个实例变量-该死的很快.

It returns an instance variable - pretty damn fast.

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