whitch Regex can i use to split XML string before and after mathml match

Question

I would like to ask which Regex i can use in order to splits the text string by <math xmlns='http://www.w3.org/1998/Math/MathML'>....</math>

the the result will be:

the code is:

        var text = @"{(test&<math xmlns='http://www.w3.org/1998/Math/MathML'><apply><plus></plus><cn>1</cn><cn>2</cn></apply></math>)|(<math xmlns='http://www.w3.org/1998/Math/MathML'><apply><root></root><degree><ci>m</ci></degree><ci>m</ci></apply></math>&nnm)&<math xmlns='http://www.w3.org/1998/Math/MathML'><apply><power></power><cn>1</cn><cn>2</cn></apply></math>#<math xmlns='http://www.w3.org/1998/Math/MathML'><set><ci>l</ci></set></math>}";
        string findTagString = "(<math.*?>)|(.+?(?=<math/>))";
        Regex findTag = new Regex(findTagString);
        List<string> textList = findTag.Split(text).ToList();

I have found a similar question at Using Regex to split XML string before and after match and i would like to ask for advice about the Regex expression

Thank you

Ori

Answer 1

经过一些测试，我认为这可以完成工作：

string findTagString = "(<math.*?></math>)|((.*){}()#&(.*))</math>";

Answer 2

Here is my attempt, based on a zero-length look-ahead and look-behind:

(?=<math[^>]*>)|(?<=</math>)

Code:

string findTagString = "(?=<math[^>]*>)|(?<=</math>)";
var text = @"{(test&<math xmlns='http://www.w3.org/1998/Math/MathML'><apply><plus></plus><cn>1</cn><cn>2</cn></apply></math>)|(<math xmlns='http://www.w3.org/1998/Math/MathML'><apply><root></root><degree><ci>m</ci></degree><ci>m</ci></apply></math>&nnm)&<math xmlns='http://www.w3.org/1998/Math/MathML'><apply><power></power><cn>1</cn><cn>2</cn></apply></math>#<math xmlns='http://www.w3.org/1998/Math/MathML'><set><ci>l</ci></set></math>}";
Regex findTag = new Regex(findTagString);
string[] textList = findTag.Split(text);
Console.WriteLine(string.Join("\n", textList));

Output of a sample program :

{(test&                                                                                                                                                             
<math xmlns='http://www.w3.org/1998/Math/MathML'><apply><plus></plus><cn>1</cn><cn>2</cn></apply></math>                                                            
)|(                                                                                                                                                                 
<math xmlns='http://www.w3.org/1998/Math/MathML'><apply><root></root><degree><ci>m</ci></degree><ci>m</ci></apply></math>                                           
&nnm)&                                                                                                                                                              
<math xmlns='http://www.w3.org/1998/Math/MathML'><apply><power></power><cn>1</cn><cn>2</cn></apply></math>                                                          
#                                                                                                                                                                   
<math xmlns='http://www.w3.org/1998/Math/MathML'><set><ci>l</ci></set></math>                                                                                       
}     

Answer 3

I would advise against trying to use regular expressions with XML. XML is not a regular language and thus not fitting for regular expressions. Anyway .NET gives such convenient tools for parsing XML that I really don't see the point.

My suggestion is that you use LINQ to XML instead of regexs.