How remove some special words from a string content?

Question

I have some strings containing code for emoji icons, like :grinning:, :kissing_heart:, or :bouquet:. I'd like to process them to remove the emoji codes.

For example, given:

Hello:grinning: , how are you?:kissing_heart: Are you fine?:bouquet:

I want to get this:

Hello , how are you? Are you fine?

I know I can use this code:

richTextBox2.Text = richTextBox1.Text.Replace(":kissing_heart:", "").Replace(":bouquet:", "").Replace(":grinning:", "").ToString();

However, there are 856 different emoji icons I have to remove (which, using this method, would take 856 calls to Replace()). Is there any other way to accomplish this?

Answer 1

You can use Regex to match the word between :anything:. Using Replace with function you can make other validation.

string pattern = @":(.*?):";
string input = "Hello:grinning: , how are you?:kissing_heart: Are you fine?:bouquet: Are you super fan, for example. :words not to replace:";
string output = Regex.Replace(input, pattern, (m) =>
{
    if (m.ToString().Split(' ').Count() > 1) // more than 1 word and other validations that will help preventing parsing the user text
    {
        return m.ToString();
    }
    return String.Empty;
}); // "Hello , how are you? Are you fine? Are you super fan, for example. :words not to replace:"

If you don't want to use Replace that make use of a lambda expression, you can use \w, as @yorye-nathan mentioned, to match only words.

string pattern = @":(\w*):";
string input = "Hello:grinning: , how are you?:kissing_heart: Are you fine?:bouquet: Are you super fan, for example. :words not to replace:";
string output = Regex.Replace(input, pattern, String.Empty); // "Hello , how are you? Are you fine? Are you super fan, for example. :words not to replace:"

Answer 2

string Text = "Hello:grinning: , how are you?:kissing_heart: Are you fine?:bouquet:";

i would solve it that way

List<string> Emoj = new List<string>() { ":kissing_heart:", ":bouquet:", ":grinning:" };
Emoj.ForEach(x => Text = Text.Replace(x, string.Empty));

UPDATE - refering to Detail's Comment

Another approach: replace only existing Emojs

List<string> Emoj = new List<string>() { ":kissing_heart:", ":bouquet:", ":grinning:" };
var Matches = Regex.Matches(Text, @":(\w*):").Cast<Match>().Select(x => x.Value);
Emoj.Intersect(Matches).ToList().ForEach(x => Text = Text.Replace(x, string.Empty));

But i'm not sure if it's that big difference for such short chat-strings and it's more important to have code that's easy to read/maintain. OP's question was about reducing redundancy Text.Replace().Text.Replace() and not about the most efficient solution.