有什么用\u和\x而代表字符文字之间的差异 [英] What is the difference between using \u and \x while representing character literal

问题描述

我所看到的 \u 和 \x 而代表字符文字在一些地方互换使用。

I have seen \u and \x used interchangeably in some places while representing a character literal.

例如'\\\©'=='\x00A9计算结果为真正

难道我们不是应该只使用 \u 来表示Unicode字符？什么是使用具有两种方式来表示一个字符的？

Aren't we supposed to use only \u to represent unicode character? What is the use of having two ways to represent a character?

推荐答案

我的强烈的唯一建议使用 \u ，因为它更容易出错。

I would strongly recommend only using \u, as it's much less error-prone.

\x 消耗1-4个字符，只要它们是十六进制数字 - 而 \u 必须的总是的遵循4十六进制数字。从C＃5规范，部分2.4.4.4，语法为 \x ：

\x consumes 1-4 characters, so long as they're hex digits - whereas \u must always be followed by 4 hex digits. From the C# 5 specification, section 2.4.4.4, the grammar for \x:

的十六进制转义序列：的结果
&NBSP;&NBSP; \x 的进制的进制的<子>选择的进制的<子>选择的进制的<子>选择

hexadecimal-escape-sequence:
  \x hex-digit hex-digit_opt hex-digit_opt hex-digit_opt

因此，例如：

string good = "Tab\x9Good compiler";
string bad =  "Tab\x9Bad compiler";

...看起来相似，但的非常的不同的字符串，因为后者有效地标签，然后按 U + 9BAD 其次是的编译器。

... look similar but are very different strings, as the latter is effectively "Tab" followed by U+9BAD followed by " compiler".

我个人希望C＃语言从来没有包括 \x ，但我们走了。

Personally I wish the C# language had never included \x, but there we go.

请注意，有也 \U ，它总是跟着8个十六进制数字，主要用于非BMP字符。

Note that there's also \U, which is always followed by 8 hex digits, primarily used for non-BMP characters.

有间<另外一个很大的区别code> \u 和 \x ：后者的只有 ，而 \u 也可以在标识中使用：

There's one other big difference between \u and \x: the latter is only used in character and string literals, whereas \u can also be used in identifiers:

string x = "just a normal string";
Console.WriteLine(\u0078); // Still refers to the identifier x

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