Question

Say I have the string ‘User Name:firstname.surname’ contained in a larger string how can I use a regular expression to just get the firstname.surname part?

Every method i have tried returns the string ‘User Name:firstname.surname’ then I have to do a string replace on ‘User Name:’ to an empty string.

Could back references be of use here?

Edit:

The longer string could contain ‘Account Name: firstname.surname’ hence why I want to match the ‘User Name:’ part of the string aswell to just get that value.

Answer 1

I like to use named groups:

Match m = Regex.Match('User Name:first.sur', @'User Name:(?<name>\w+\.\w+)'); if(m.Success) {    string name = m.Groups['name'].Value; } 

Putting the ?<something> at the beginning of a group in parentheses (e.g. (?<something>...)) allows you to get the value from the match using something as a key (e.g. from m.Groups['something'].Value)

If you didn’t want to go to the trouble of naming your groups, you could say

Match m = Regex.Match('User Name:first.sur', @'User Name:(\w+\.\w+)'); if(m.Success) {    string name = m.Groups[1].Value; } 

and just get the first thing that matches. (Note that the first parenthesized group is at index 1; the whole expression that matches is at index 0)