RegEx - reusing subexpressions

Question

Say I have a regex matching a hexadecimal 32 bit number:

([0-9a-fA-F]{1,8})

When I construct a regex where I need to match this multiple ti

Answer 1

If I am understanding your question correctly, you want to reuse certain patterns to construct a bigger pattern?

string f = @"fc\d+/";
string e = @"\d+";
Regex regexObj = new Regex(f+e);

Other than this, using backreferences will only help if you are trying to match the exact same string that you have previously matched somewhere in your regex.

e.g.

/\b([a-z])\w+\1\b/

Will only match : text, spaces in the above text :

This is a sample text which is not the title since it does not end with 2 spaces.