由网友(心如止水)分享简介：我的这些示例性类型的字符串：I have these examplary type strings:"System.Collections.Generic.IEnumerable`1[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, Public...

我的这些示例性类型的字符串：

I have these examplary type strings:

"System.Collections.Generic.IEnumerable`1[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"

"System.Collections.IEnumerable"

"System.Collections.Generic.Dictionary`2[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Type, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"

"Whatever`3[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[ImaginaryType],[System.Type, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"

使用正则表达式，我想提取的主要类型，它的泛型类型统计，所有的泛型类型本身，所以上面的四个例子，我赶这些元素相应：

Using regex, I want to extract the main-type, its generic types count, and all the generic types themselves, so for the four examples above, I "catch" these elements correspondingly:

"System.Collections.Generic.IEnumerable"
    1
    "System.String"

"System.Collections.IEnumerable"
    0

"System.Collections.Generic.Dictionary"
    2
    "System.Int32"
    "System.Type"

"Whatever"
    3
    "System.Int32"
    "ImaginaryType"
    "System.Type"

有一个正则表达式可以做到这一点？

Is there a regex that can do that?

推荐答案

你可以用这种模式做到这一点：

you can do it with this pattern:

string pattern = @"
(?:   # two possible entry points
    G(?!A)       # contigous to the precedent match
  |                # OR
    A             # at the start of the string
    (?<main> [^`]+ )  ` (?<number> [0-9]+ ) [
)

[ (?<type> [^],]+ ) # generic type
[^]]* ]              # all until the next closing square bracket
(?: , | ]z )

| A (?<main> [^`]+ ) # or a main-type without generic types
";

RegexOptions options = RegexOptions.IgnorePatternWhitespace;

foreach (Match match in Regex.Matches(input, pattern, options)) { ...

如果你的项目使用的模式几次，最好是一劳永逸编译。 请注意，您可以使用这个变量，而不是降低了正则表达式引擎的工作：

If you project to use the pattern several times, it's better to compile it once and for all. Note that you can reduce the regex engine work using this variant instead:

string pattern = @"
  G(?!A) [
  (?<type> [^],]+ )
  [^]]* ] (?: , | ]z )
|
  A
  (?<main> [^`]+ ) 
  (?:
      ` (?<number> [0-9]+ )
      [{2}
      (?<type> [^],]+ )
      [^]]* ]
      (?: , | ]z )
    |
      z
  )";

如果你想确保字符串的结尾已经达到可以取代] Z 与（小于？endcheck＆GT;] Z）键，如果组存在于最后一场比赛的控制。

If you want to ensure that the end of the string has been reached you can replace ]z with (?<endcheck>]z) and control if the group exist in the last match.