C＃替换部分消息

Question

string message = "Your purchase of $ 100.00 is awaiting for confirmation. Please use PIN 8967 to complete the transaction. Reference Number :1237689";

string output = Regex.Replace(message, @"[\d-]", "*");

Console.WriteLine("Message : " + message);

Console.WriteLine("Output : " + output);

Console.ReadLine();

I want to only replace the PIN of the message. But above message replace all the numeric values from * characters.

Answer 1

string message = "Your purchase of $ 100.00 is awaiting for confirmation. Please use PIN 8967 to complete the transaction. Reference Number :1237689";
string output = Regex.Replace(message, @"(?<=PIN\s*\d*)\d", "*");

or

string message = "Your purchase of $ 100.00 is awaiting for confirmation. Please use PIN 8967 to complete the transaction. Reference Number :1237689";
string output = Regex.Replace(message, @"(?<=PIN\s*)\d+", m => new string('*', m.Length));