为什么我可以在字符串中添加字符，但不能在字符中添加字符？ [英] Why can I add characters to strings but not characters to characters?

问题描述

因此，我想在字符串中添加一个字符，在某些情况下，我想将该字符加倍，然后将其添加到字符串中（即首先添加到其自身中）。我尝试了如下操作。

So I wanted to add a character to a string, and in some cases wanted to double that characters then add it to a string (i.e. add to it itself first). I tried this as shown below.

char s = 'X'; 
String string = s + s;

这引发了错误，但是我已经在字符串中添加了单个字符，所以我尝试了：

This threw up an error, but I'd already added a single character to a string so I tried:

String string = "" + s + s;

曾工作过。为什么在求和中包含字符串会导致它起作用？是否要添加字符串属性，该字符串属性由于存在字符串而只能在字符转换为字符串时使用？

Which worked. Why does the inclusion of a string in the summation cause it to work? Is adding a string property which can only be used by characters when they're converted to strings due to the presence of a string?

推荐答案

这是因为String + Char = String，类似于int + double = double的方式。

It's because String + Char = String, similar to how an int + double = double.

Char + Char的数据是int的，尽管其他答案告诉您。

Char + Char is int despite what the other answers tell you.

字符串s = 1; //由于类型不匹配而导致的编译错误。

String s = 1; // compilation error due to mismatched types.

您的工作代码为（String + Char）+ Char。如果您这样做：String +（Char + Char），您将在字符串中得到一个数字。示例：

Your working code is (String+Char)+Char. If you had done this: String+(Char+Char) you would get a number in your string. Example:

System.out.println("" + ('x' + 'x')); // prints 240
System.out.println(("" + 'x') + 'x'); // prints xx - this is the same as leaving out the ( ).

这篇关于为什么我可以在字符串中添加字符，但不能在字符中添加字符？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！