Question

An input string:

string datar = "aag, afg, agg, arg";

I am trying to get matches: “aag” and “arg”, but following won’t work:

string regr = "a[a-z&&[^fg]]g";
string regr = "a[a-z[^fg]]g";

What is the correct way of ignoring regex matches in C#?

Answer 1

The obvious way is to use a[a-eh-z]g, but you could also try with a negative lookbehind like this :

string regr = "a[a-z](?<!f|g)g"

Explanation :

• a Match the character “a”
• [a-z] Match a single character in the range between “a” and “z”
• (?<!XXX) Assert that it is impossible to match the regex below with the match ending at this position (negative lookbehind)
  • f|g Match the character “f” or match the character “g”
• g Match the character “g”