Question

I would like to supply my regular expression with a ‘default’ value, so if the thing I was looking for is not found, it will return the default value as if it had found it.

Is this possible to do using regex?

Answer 1

It sounds like you want some sort of regex syntax that says “if the regexp does not match any part of the given string pretend that it matched the following substring: ‘foobar'”. Such a feature does not exist in any regexp syntax I’ve seen.

You’ll probably need to something like this:

matched_string = string.find_regex_match(regex);
if(matched_string == null) {
  string = "default";
}

(This will of course need to be adjusted to the language you’re using)