Replace emoticon with word in tweet using regex c#

Question

Basically the idea is to map the emoticons in the string to actual words. say for :) you replace it with happy. A more clear example would be. Original: Today is a sunny day :). But tomorrow it is going to rain :(. Final: Today is a sunny day happy. But tomorrow it is going to rain sad.

I have trying a solution using a common regex for all emoticons but I am not sure once you detect it is an emoticon, how to go back and replace each one with appropriate word. I need it only for three emoticons :),:( and :D. Thank you.

Answer 1

Use Regex.Replace method that takes a custom match evaluator.

static string ReplaceSmile(Match m) {
    string x = m.ToString();
    if (x.Equals(":)")) {
        return "happy";
    } else if (x.Equals(":(")) {
        return "sad";
    }
    return x;
}

static void Main() {
    string text = "Today is a sunny day :). But tomorrow it is going to rain :(";
    Regex rx = new Regex(@":[()]");
    string result = rx.Replace(text, new MatchEvaluator(ReplaceSmile));
    System.Console.WriteLine("result=[" + result + "]");
}