C# 如何使用正则表达式在特定字符串/字符之后找到字符串
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/454414/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How can I find a string after a specific string/character using regex
提问by Flo
I am hopeless with regex (c#) so I would appreciate some help:
我对正则表达式（c#）感到绝望，所以我希望得到一些帮助：
Basicaly I need to parse a text and I need to find the following information inside the text:
基本上我需要解析一个文本，我需要在文本中找到以下信息：
Sample text:
示例文本：
KeywordB:***TextToFind* the rest is not relevant but **KeywordB:Text ToFindBand then some more text.
KeywordB:***TextToFind* 其余不相关，但 **KeywordB: Text ToFindB然后是更多文本。
I need to find the word(s) after a certain keyword which may end with a “:”.
我需要在某个可能以“:”结尾的关键字之后找到单词。
[UPDATE]
[更新]
Thanks Andrew and Alan: Sorry for reopening the question but there is quite an important thing missing in that regex. As I wrote in my last comment, Is it possible to have a variable (how many words to look for, depending on the keyword) as part of the regex?
谢谢 Andrew 和 Alan：很抱歉重新打开这个问题，但该正则表达式中缺少一件非常重要的事情。正如我在上一条评论中所写的那样，是否可以将变量（要查找多少个单词，取决于关键字）作为正则表达式的一部分？
Or: I could have a different regex for each keyword (will only be a hand full). But still don't know how to have the "words to look for" constant inside the regex
或者：我可以为每个关键字使用不同的正则表达式（只会满手）。但仍然不知道如何在正则表达式中保持“要查找的词”常量
采纳答案by Andrew Backer
Let me know if I should delete the old post, but perhaps someone wants to read it.
让我知道我是否应该删除旧帖子，但也许有人想阅读它。
The way to do a "words to look for" inside the regex is like this:
在正则表达式中做一个“要查找的词”的方法是这样的：
regex = @"(Key1|Key2|Key3|LastName|FirstName|Etc):"
What you are doing probably isn't worth the effort in a regex, though it can probablybe done the way you want (still not 100% clear on requirements, though). It involves looking ahead to the next match, and stopping at that point.
您正在做的事情可能不值得在正则表达式中付出努力，尽管它可能可以按照您想要的方式完成（尽管需求仍然不是 100% 明确）。它涉及展望下一场比赛，并在那个点停下来。
Here is a re-write as a regex + regular functional code that should do the trick. It doesn't care about spaces, so if you ask for "Key2" like below, it will separate it from the value.
这是一个重新编写的正则表达式 + 常规功能代码，应该可以解决问题。它不关心空格，所以如果你像下面这样要求“Key2”，它会将它与值分开。
string[] keys = {"Key1", "Key2", "Key3"};
string source = "Key1:Value1Key2: ValueAnd A: To Test Key3: Something";
FindKeys(keys, source);
private void FindKeys(IEnumerable<string> keywords, string source) {
var found = new Dictionary<string, string>(10);
var keys = string.Join("|", keywords.ToArray());
var matches = Regex.Matches(source, @"(?<key>" + keys + "):",
RegexOptions.IgnoreCase);
foreach (Match m in matches) {
var key = m.Groups["key"].ToString();
var start = m.Index + m.Length;
var nx = m.NextMatch();
var end = (nx.Success ? nx.Index : source.Length);
found.Add(key, source.Substring(start, end - start));
}
foreach (var n in found) {
Console.WriteLine("Key={0}, Value={1}", n.Key, n.Value);
}
}
And the output from this is:
并且由此产生的输出是：
Key=Key1, Value=Value1
Key=Key2, Value= ValueAnd A: To Test
Key=Key3, Value= Something
回答by Tiago
/KeywordB\: (\w)/
This matches any word that comes after your keyword. As you didn′t mentioned any terminator, I assumed that you wanted only the word next to the keyword.
这匹配您的关键字之后的任何单词。由于您没有提到任何终止符，我假设您只需要关键字旁边的单词。
回答by Andrew Backer
The basic regex is this:
基本的正则表达式是这样的：
var pattern = @"KeywordB:\s*(\w*)";
\s* = any number of spaces
\w* = 0 or more word characters (non-space, basically)
() = make a group, so you can extract the part that matched
var pattern = @"KeywordB:\s*(\w*)";
var test = @"KeywordB: TextToFind";
var match = Regex.Match(test, pattern);
if (match.Success) {
Console.Write("Value found = {0}", match.Groups[1]);
}
If you have more than one of these on a line, you can use this:
如果您在一行中有多个这些，您可以使用这个：
var test = @"KeywordB: TextToFind KeyWordF: MoreText";
var matches = Regex.Matches(test, @"(?:\s*(?<key>\w*):\s?(?<value>\w*))");
foreach (Match f in matches ) {
Console.WriteLine("Keyword '{0}' = '{1}'", f.Groups["key"], f.Groups["value"]);
}
Also, check out the regex designer here: http://www.radsoftware.com.au/. It is free, and I use it constantly. It works great to prototype expressions. You need to rearrange the UI for basic work, but after that it's easy.
另外，请在此处查看正则表达式设计器：http: //www.radsoftware.com.au/。它是免费的，我经常使用它。它适用于原型表达式。您需要为基本工作重新安排 UI，但之后就很容易了。
(fyi) The "@" before strings means that \ no longer means something special, so you can type @"c:\fun.txt" instead of "c:\fun.txt"
(fyi) 字符串前的“@”意味着\不再意味着特殊的东西，所以你可以输入@"c:\fun.txt"而不是"c:\fun.txt"
