C# Regex.Match 大括号-仅内容？（不包括大括号）
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C# Regex.Match curly brackets- contents only? (exclude braces)
提问by PeterX
I've been unable to find an answer on this: can I use the Regex.Matchesmethod to return only the contentsof items with curly braces?
我一直无法找到答案：我可以使用该Regex.Matches方法仅返回带花括号的项目的内容吗？
If I use the Regex ({[^}]*})my MatchCollectionvalues includes the braces. I want to match, but then only return the contents. Here's what I have so far:
如果我使用正则表达式，({[^}]*})我的MatchCollection值包括大括号。我想匹配，但只返回内容。这是我到目前为止所拥有的：
Regex regex = new Regex(({[^}]*}), RegexOptions.IgnoreCase);
MatchCollection matches = regex.Matches("Test {Token1} {Token 2}");
// Results include braces (undesirable)
var results = matches.Cast<Match>().Select(m => m.Value).Distinct().ToList();
采纳答案by Milosz Krajewski
I always liked it explicit. So you can use "positive lookbehind" (?<=...) and "positive lookahead" (?=...) groups:
我一直喜欢它明确的。所以你可以使用“positive lookbehind” (?<=...) 和“positive lookahead” (?=...) 组：
(?<=\{)
[^}]*
(?=\})
which means:
意思是：
- require opening curly bracket beforematch
- collect text (of, course) - as commented before I may be [^{}]* as well
- require closing curly bracket aftermatch
- 需要在匹配前打开大括号
- 收集文本（当然） - 正如我之前评论的那样，我也可能是 [^{}]*
- 匹配后需要关闭大括号
回答by RichieHindle
Just move the braces outside the parentheses:
只需将大括号移到括号外：
{([^}]*)}
回答by UberMouse
If I understand what you want. Change the regex to {([^}]*)}. That will only capture the text between {}, not including them.
如果我明白你想要什么。将正则表达式更改为{([^}]*)}. 这只会捕获 {} 之间的文本，而不包括它们。
回答by bunjeeb
Thanks Milosz Krajewski, Nothing to add but here is the function
感谢 Milosz Krajewski，没什么可添加的，但这里是功能
private List<String> GetTokens(String str)
{
Regex regex = new Regex(@"(?<=\{)[^}]*(?=\})", RegexOptions.IgnoreCase);
MatchCollection matches = regex.Matches(str);
// Results include braces (undesirable)
return matches.Cast<Match>().Select(m => m.Value).Distinct().ToList();
}
回答by RajeshValangaiman
It is regex for C# .net.
它是 C# .net 的正则表达式。
@"{(.*?)}"
it display a
它显示一个
token1 token2
令牌1 令牌2
回答by Wiktor Stribi?ew
In C#, as in many other programming language, the regex engine supports capturing groups, that are submatches, parts of substrings that match a whole regex pattern, defined in a regex pattern with the help of parentheses (e.g. 1([0-9])3will match 123and save the value of 2into a capture group 1 buffer). Captured texts are accessed via Match.Groups[n].Valuewhere nis the index of the capture group inside the pattern.
在C＃中，正如在许多其他的编程语言，正则表达式引擎支持捕获组，是子匹配，匹配整个正则表达式模式的子字符串的部分，用括号的帮助下，正则表达式模式定义（如1([0-9])3将匹配123和保存价值2进入捕获组 1 缓冲区）。捕获的文本通过以下方式访问，Match.Groups[n].Value其中n是模式内捕获组的索引。
Capturing is much more effecient that lookarounds. Whenever there is no need for complex conditions, capturing groups are much better alternatives.
捕获比环视更有效。当不需要复杂条件时，捕获组是更好的选择。
See my regex speed test performed at regexhero.net:
请参阅我在 regexhero.net 上执行的正则表达式速度测试：
Now, how can we get the substring inside curly braces?
现在，我们如何获得花括号内的子字符串？
- if there is no other curly braces inside, with a negated character class:
{([^{}]*) - if there can be nested curly brackets:
{((?>[^{}]+|{(?<c>)|}(?<-c>))*(?(c)(?!)))
- 如果里面没有其他花括号，带有否定字符类：
{([^{}]*) - 如果可以嵌套大括号：
{((?>[^{}]+|{(?<c>)|}(?<-c>))*(?(c)(?!)))
In both cases, we match an opening {, and then match (1) any character other than {or }, or (2) any characters up to the first paired }.
在这两种情况下，我们匹配开头{，然后匹配 (1) 除{or之外的任何字符}，或 (2) 直到第一个配对的任何字符}。
Here is sample code:
这是示例代码：
var matches = Regex.Matches("Test {Token1} {Token 2}", @"{([^{}]*)");
var results = matches.Cast<Match>().Select(m => m.Groups[1].Value).Distinct().ToList();
Console.WriteLine(String.Join(", ", results));
matches = Regex.Matches("Test {Token1} {Token {2}}", @"{((?>[^{}]+|{(?<c>)|}(?<-c>))*(?(c)(?!)))");
results = matches.Cast<Match>().Select(m => m.Groups[1].Value).Distinct().ToList();
Console.WriteLine(String.Join(", ", results));
Result: Token1, Token 2, Token1, Token {2}.
结果：Token1, Token 2, Token1, Token {2}。
Note that RegexOptions.IgnoreCaseis redundant when you have no literal letters that can have different case in the pattern.
请注意，RegexOptions.IgnoreCase当您没有可以在模式中具有不同大小写的文字字母时，这是多余的。
回答by sumit sharma
Little bit modifying the answer of @Milosz Krajewski
稍微修改@Milosz Krajewski 的答案
(?<=\{)[^}{]*(?=\})
this will skip the middle single opening and closing Curly braces in the string.
这将跳过字符串中中间的单个打开和关闭花括号。
