Question

I have a string that may contain XML and normal string. I need to parse out the <math....</math> for all instances in a string. How can I parse out multiple sections of this (from <math> to </math>) from this string?

Here is some content <math
xmlns="http://www.w3.org/1998/Math/MathML">  
<mi>a</mi><mo>&#x2260;</mo><mn>0</mn> </math>, that is mixed in with
this other content <math xmlns="http://www.w3.org/1998/Math/MathML">  
<mi>a</mi><msup><mi>x</mi><mn>2</mn></msup>   <mo>+</mo>
<mi>b</mi><mi>x</mi>   <mo>+</mo> <mi>c</mi> <mo>=</mo> <mn>0</mn>
</math> we want to be able to seperate this string

Background:
I tried to make this question generic. The specifics of what I’m trying to do is for MVC3 encoding versus Raw. It will encode everything by default. I don’t want it to encode MathML, but do want it to encode everything else. So parts of it I want to render out as Html.Raw (the MathML part) and the rest I want to render as normally encoded strings.

Answer 1

I’m no regular expression boffin, but this is what I tried and I got back the correct result. Please use it as a base and modify it where necessary.

I got it from this post on Stackoverflow.

string yourstring = "<math xmlns=\"http://www.w3.org/1998/Math/MathML\">   <mi>a</mi><mo>&#x2260;</mo><mn>0</mn> </math>, that is mixed in with this other content <math xmlns=\"http://www.w3.org/1998/Math/MathML\">   <mi>a</mi><msup><mi>x</mi><mn>2</mn></msup>   <mo>+</mo> <mi>b</mi><mi>x</mi>   <mo>+</mo> <mi>c</mi> <mo>=</mo> <mn>0</mn> </math>";

try
{
     yourstring = Regex.Replace(yourstring, "(<math[^>]+>.+?</math>)", "");
}
catch (ArgumentException ex)
{
     // Syntax error in the regular expression
}

The resulting string is:

, that is mixed in with this other content