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

Why not do something like this, not really shorter but a bit more maintainable.

String.Format("(?{0})\s*:\s*(?{0})", "[0-9a-zA-Z]{1,8}");

If you want more self documenting code i would assign the number regex string to a properly named const variable.