Question

I have a string that could have any sentence in it but somewhere in that string will be the @ symbol, followed by an attached word, sort of like @username you see on some sites.

so maybe the string is “hey how are you” or it’s “@john hey how are you”.

IF there’s an “@” in the string i want to pull what comes immediately after it into its own new string.

in this instance how can i pull “john” into a different string so i could theoretically notify this person of his new message? i’m trying to play with string.contains or .replace but i’m pretty new and having a hard time.

this btw is in c# asp.net

Answer 1

You should really learn regular expressions. This will work for you:

using System.Text.RegularExpressions;

var res = Regex.Match("hey @john how are you", @"@(\S+)");

if (res.Success)
{
    //john
    var name = res.Groups[1].Value;
}

Finds the first occurrence. If you want to find all you can use Regex.Matches. \S means anything else than a whitespace. This means it also make hey @john, how are you => john, and @john123 => john123 which may be wrong. Maybe [a-zA-Z] or similar would suit you better (depends on which characters the usernames is made of). If you would give more examples, I could tune it 🙂

I can recommend this page:

http://www.regular-expressions.info/

and this tool where you can test your statements:

http://regexlib.com/RESilverlight.aspx