Java中的长度和长度() [英] length and length() in Java

问题描述

为什么我们有一个数组的长度作为属性，array.length，而对于String，我们有一个方法，str.length()?

有什么原因吗?

解决方案

让我首先强调三种不同的方式来达到类似的目的.

length -- 数组 (int[], double[], String[]) -- 知道数组的长度

length() -- 字符串相关对象(String, StringBuilder, etc) -- 要知道字符串的长度

size() -- Collection Object (ArrayList, Set, etc) -- 要知道集合的大小

现在忘记 length() 只考虑 length 和 size().

length 不是一个方法，所以它对对象不起作用是完全合理的.它只适用于数组.
size() 它的名字更好地描述了它，因为它是一种方法，它将用于那些使用集合(集合框架)的对象，正如我上面所说的那样.

现在来到length():
String 不是原始数组(所以我们不能使用 .length)，也不是集合(所以我们不能使用 .size())这就是为什么我们还需要另一个是 length()(保留差异并达到目的).

作为对为什么?
的回答我觉得它很有用，易于记忆和使用，而且很友好.

Why do we have the length of an array as an attribute, array.length, and for String we have a method, str.length()?

Is there some reason?

解决方案

Let me first highlight three different ways for similar purpose.

length -- arrays (int[], double[], String[]) -- to know the length of the arrays

length() -- String related Object (String, StringBuilder, etc) -- to know the length of the String

size() -- Collection Object (ArrayList, Set, etc) -- to know the size of the Collection

Now forget about length() consider just length and size().

length is not a method, so it completely makes sense that it will not work on objects. It only works on arrays.
size() its name describes it better and as it is a method, it will be used in the case of those objects who work with collection (collection frameworks) as I said up there.

Now come to length():
String is not a primitive array (so we can't use .length) and also not a Collection (so we cant use .size()) that's why we also need a different one which is length() (keep the differences and serve the purpose).

As answer to Why?
I find it useful, easy to remember and use and friendly.

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