C# Regex.Replace match by the same amount of characters

Question

I like to know how to replace a regex-match of unknown amount of equal-signs, thats not less than 2... to the same amount of underscores

So far I got this:

Answer 1

You can use Regex.Replace(String, MatchEvaluator) instead and analyze math:

string result = new Regex("(={2,})")
    .Replace(text, match => new string('_', match.ToString().Length));