如何将 Unicode 转义序列转换为 .NET 字符串中的 Unicode 字符? [英] How do I convert Unicode escape sequences to Unicode characters in a .NET string?

问题描述

假设您已将一个文本文件加载到一个字符串中，并且您想将所有 Unicode 转义符转换为字符串中的实际 Unicode 字符.

Say you've loaded a text file into a string, and you'd like to convert all Unicode escapes into actual Unicode characters inside of the string.

示例:

下面是Unicode 'u2320'中整数字符的上半部分，这是'U2321'的下半部分."

"The following is the top half of an integral character in Unicode 'u2320', and this is the lower half 'U2321'."

推荐答案

答案很简单，并且适用于至少几千个字符的字符串.

The answer is simple and works well with strings up to at least several thousand characters.

示例 1:

Regex  rx = new Regex( @"\[uU]([0-9A-F]{4})" );
result = rx.Replace( result, match => ((char) Int32.Parse(match.Value.Substring(2), NumberStyles.HexNumber)).ToString() );

示例 2:

Regex  rx = new Regex( @"\[uU]([0-9A-F]{4})" );
result = rx.Replace( result, delegate (Match match) { return ((char) Int32.Parse(match.Value.Substring(2), NumberStyles.HexNumber)).ToString(); } );

第一个示例显示使用 lambda 表达式 (C# 3.0) 进行的替换，第二个示例使用应与 C# 2.0 一起使用的委托.

The first example shows the replacement being made using a lambda expression (C# 3.0) and the second uses a delegate which should work with C# 2.0.

要分解这里发生的事情，首先我们创建一个正则表达式:

To break down what's going on here, first we create a regular expression:

new Regex( @"\[uU]([0-9A-F]{4})" );

然后我们用字符串'result'和一个匿名方法(第一个例子中的lambda表达式和第二个例子中的委托——委托也可以是一个正则方法)调用Replace()，它转换找到的每个正则表达式在字符串中.

Then we call Replace() with the string 'result' and an anonymous method (lambda expression in the first example and the delegate in the second - the delegate could also be a regular method) that converts each regular expression that is found in the string.

Unicode 转义是这样处理的:

The Unicode escape is processed like this:

((char) Int32.Parse(match.Value.Substring(2), NumberStyles.HexNumber)).ToString(); });

获取表示转义数字部分的字符串(跳过前两个字符).

Get the string representing the number part of the escape (skip the first two characters).

match.Value.Substring(2)

使用 Int32.Parse() 解析该字符串，它接受字符串和 Parse() 函数应该期望的数字格式，在这种情况下是一个十六进制数字.

Parse that string using Int32.Parse() which takes the string and the number format that the Parse() function should expect which in this case is a hex number.

NumberStyles.HexNumber

然后我们将结果数字转换为 Unicode 字符:

Then we cast the resulting number to a Unicode character:

(char)

最后，我们在 Unicode 字符上调用 ToString()，它为我们提供字符串表示形式，即传递回 Replace() 的值:

And finally we call ToString() on the Unicode character which gives us its string representation which is the value passed back to Replace():

.ToString()

注意:您可以使用 match 参数的 GroupCollection 和正则表达式中的子表达式，而不是通过 Substring 调用获取要转换的文本，以仅捕获数字 ('2320')，但这更复杂且可读性较差.

Note: Instead of grabbing the text to be converted with a Substring call you could use the match parameter's GroupCollection, and a subexpressions in the regular expression to capture just the number ('2320'), but that's more complicated and less readable.

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