Question

I need a RegEx pattern that will allow me to substitute characters from one set to their corresponding characters in another set. for example: set [abcdefg], should be replaced with set [1234567]… So in a string of “bag”, i want my replacement to be “217”.

Regex regX = new Regex("([abcdefg])([1234567])");
string result = regX.Replace("bag", "$1$2");

My result is same as source. What should my replace pattern be?

Answer 1

Something like this will work much better than a Regex:

var fromCharacters = "abcdefghijklmnopqrstuvwxyz";
var toCharacters = "12345678901234567890123456";

var myString = "bag";

var sb = new StringBuilder(myString.Length);
for (int i = 0; i < myString.Length; ++i)
{
    sb.Append(toCharacters[fromCharacters.IndexOf(myString[i])]);
}

sb.ToString().Dump();

You could do something similar if you want, for example, ‘j’ to turn into ’10’, but you would need an array of Strings instead of being able to use a String as an array of chars.

I’m not sure how you would do this with a Regex, but I do know that you shouldn’t.