Question

I would like to format a string that looks like this

BPT4SH9R0XJ6

Into something that looks like this

BPT4-SH9R-0XJ6

The string will always be a mix of 12 letters and numbers

Any advice will be highly appreciated, thanks

Answer 1

Try Regex.Replace(input, @"(\w{4})(\w{4})(\w{4})", @"$1-$2-$3");

Regex is often derided, but is a pretty neat way of doing what you need. Can be extended to more complex requirements that are difficult to meet using string methods.