此正则表达式中单引号的目的是什么? [英] What is the purpose of the single quotes in this regex expression?

问题描述

我已经使用以下正则表达式继承了一些C#代码

I've inherited some C# code with the following regular expression

Regex(@"^[a-zA-Z''-'\s]{1,40}$")

除了单引号的作用之外，我了解此字符串.我到处搜索，但似乎找不到解释.有什么想法吗?

I understand this string except for the role of the single quotes. I've searched all over but can't seem to find an explanation. Any ideas?

推荐答案

据我所知，该表达式是多余的.

From what I can tell, the expression is redundant.

它匹配 az 或 AZ ，或'字符，或'和之间的任何字符'(当然，它又只是'字符或任何空格.

It matches a-z or A-Z, or the ' character, or anything between ' and ' (which of course is only the ' character again, or any whitespace.

我已经使用 RegexPal 对此进行了测试，除这些字符外，它似乎与其他任何字符都不匹配.也许该序列是由代码生成的，还是在较早的版本中用于匹配更大范围的字符?

I've tested this using RegexPal and it doesn't appear to match anything but these characters. Perhaps the sequence was generated by code, or it used to match a wider range of characters in an earlier version?

更新:从您的评论(与名字匹配)中，我将继续猜测作者认为他是在通过连字符转义用引号括起来，它并不是最出色的软件测试仪.他们可能的意思是:

UPDATE: From your comments (matching a name), I'm gonna go ahead and guess the author thought (s)he was escaping a hyphen by putting it in quotes, and wasn't the most stellar software tester. What they probably meant was:

Regex(@"^[a-zA-Z'\-\s]{1,40}$") //Escaped the hyphen

哪个也可以写成:

Regex(@"^[a-zA-Z'\s-]{1,40}$") //Put the hyphen at the end where it's not ambiguous

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