Help with regex c#

Question

I have an input string:

   access_token=f34b46f0f109d423sd4236af12d1bce7f10df108ec2183046b8f94641ebe&amp;expires_in=0&amp;user_id=37917395

Source code:

    Regex regex = new Regex("access_token=([^&]+)");
    MatchCollection matches;
    matches = regex.Matches(webBrowser1.SaveToString());
    if (matches.Count != 0 || access_token != string.Empty) {
        webBrowser1.IsEnabled = false;
        webBrowser1.IsHitTestVisible = false;
        if (access_token == string.Empty)
            access_token = matches[0].Value.Substring(13);

I get the access token but I also have to match the user_id. How can I get it?

Please help me, I'm not good at this.

You need to match user_id also?

Kirill Polishchuk
– Kirill Polishchuk

2011-07-27 10:25:34 +00:00
Commented Jul 27, 2011 at 10:25 — Kirill Polishchuk
– Kirill Polishchuk, Commented Jul 27, 2011 at 10:25
does the order matter? could user_id come first?

Bob Vale
– Bob Vale

2011-07-27 10:40:10 +00:00
Commented Jul 27, 2011 at 10:40 — Bob Vale
– Bob Vale, Commented Jul 27, 2011 at 10:40

Bob Vale · Accepted Answer · 2011-07-27 10:34:17Z

3

Assuming your string is in input This will set the variables accessToken and userId. If there is no match the values will be null.

Regex regex=new Regex("(?:access_token=(?<access>[^&]+))|(?:user_id=(?<userid>[^&]+))");
var accessToken=regex.Matches(input).OfType<Match>().Select(m=>m.Groups["access"]).Where(g=>g.Success).Select(g=>g.Value).FirstOrDefault();
var userId=regex.Matches(input).OfType<Match>().Select(m=>m.Groups["user_id"]).Where(g=>g.Success).Select(g=>g.Value).FirstOrDefault();

I usually have an extension method defined to reduce typing for me

public static string GetGroup(this MatchCollection matches,string group name) {
    return matches.OfType<Match>().Select(m=>m.Groups[name]).Where(g=>g.Success).Select(g=>g.Value).FirstOrDefault();
}

This allows me to do:

var matches=regex.Matches(input);
var accessToken=matches.GetGroup("access");
var userId=matches.GetGroup("user_id");

answered Jul 27, 2011 at 10:34

Bob Vale

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2 Comments

Bob Vale Over a year ago

Could you be more specific as to how it doesn't work, I've tested this with linqpad and your supplied string and it works fine?

Bob Vale Over a year ago

I'm guessing that you didn't have a reference to System.Linq so the OfType and Select extension methods failed

Kirill Polishchuk · Accepted Answer · 2011-07-27 10:31:50Z

2

string input = @"access_token=f34b46f0f109d423sd4236af12d1bce7f10df108ec2183046b8f94641ebe&expires_in=0&user_id=37917395";


var result = Regex.Match(input, @"access_token=([^&]+).*?user_id=([^&]+)");

var access_token = result.Groups[1].Value;
var user_id = result.Groups[2].Value;

answered Jul 27, 2011 at 10:31

Kirill Polishchuk

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