How to add characters to a string in C#

Question

Problem: I would like add characters to a phone.

So instead of displaying ###-###-####, I would like to display (###) ###-####.

I tried the foll

Answer 1

You can use a regular expression to extract the digit groups (regardless of - or () and then output in your desired format:

var digitGroups = Regex.Matches(x, @"(\d{3})-?(\d{3})-?(\d{4})")[0].Groups.Cast().Skip(1).Select(g => g.Value).ToArray();

var ans = $"({digitGroups[0]}) {digitGroups[1]}-{digitGroups[2]}";