\\ begin {enumerate}和\\ end {enumerate}之间的正则表达式

Question

So, I have a string like

\begin{enumerate}
\item My first item 
\item My second item
\end{enumerate}

And need with a Regex get the part between \\begin{enumerate} and the \\end{enumerate} . I've tried to have the pattern \\\\begin{enumerate}(.*?)\\\\end{enumerate} and in online checkers it works but not when I run my code.

Anyone in a mind of helping me out I would appreciate it.

Answer 1

You can use [\\s\\S]* instead of .* or use modifier s , since . does not contain \\n

var re = new Regex(@"\\begin{enumerate}([\s\S]*?)\\end{enumerate}");

Answer 2

You can use this regex:

(?s)\\begin{enumerate}(.*?)\\end{enumerate}

C#:

var rgx = new Regex(@"(?s)\\begin{enumerate}(.*?)\\end{enumerate}");

(?s) in the beginning of the pattern forces a dot to match newline symbols, and to match a backslash, you need to double it in a verbatim string literal, or quadruple it in a normal regular string literal.

Perhaps, you'd like to enforce case insensitive matching, too. Then, replace (?s) with (?si) .

Tested in Expresso:

Answer 3

I suppose you have an escaping problem here, use verbatim strings. Also, the braces should be escaped. And finally, did you use RegexOptions.Singleline so that the . metacharacter is allowed to match newlines?

var re = new Regex(@"\\begin\{enumerate\}(.*?)\\end\{enumerate\}", RegexOptions.Singleline);

Note the @ just before the " .

Answer 4

It looks as thought you may only want to use the text in between these tags so if thats the case you could use a positive lookbehind and lookahead and that would get you:

\\n\\item My first item \\n\\item My second item\\end

so try this instead. I have added some escape characters for you so it will work.

(?<=\\begin{enumerate}).*?(?=\\end{enumerate})

I would probably use the @ symbol instead of the escape characters as with the second answer. I think it looks easier to read.

Answer 5

You could always do this with plain old Linq. Eg:

var s = "\\begin{enumerate}\n" +
        "\\item My first item\n" +
        "\\item My second item\n" +
        "\\end{enumerate}";

var allRows = s.Split('\n').ToList();

var items = allRows
        .Skip(1)
        .Take(allRows.Count - 2)
        .Select(i => i.Replace(@"\item ", String.Empty));