Extract the value of substring from the main string

Question

I have a string like the one mentioned below.

{
    behavior_capture_widget: "<div id="ndwc"><noscript><input type="hidden" id="ndpd-spbd" name="ndpd-spbd"                            value="ndpds~~~2.4177.112540pPaGJYVmt5WCtndGlUiUcRt3aSOPQ,,"></noscript></div> <script type="text/javascript"></script>"
    customer_session_data:   "2.4177.112540.1399312572.2.mFDzrW_JJeu-C_H45O5ADQ"
    customer_cookie_data:    "2.4177.112540.1399312572.2.XYjAsjFsOVHFXBGNnnHc-g,,."
}

I will always get the string in this format. Values may vary.

I have to extract the value of

behavior_capture_widget
customer_session_data
customer_cookie_data

in variables a,b,c

I m new in c# and I tried to use the combination of substring() , indexof() but for no avail Help would be appreciated.

Thanks in advance.

Answer 1

Instead of using substring, you could use string.Split to get you most of the way there:

var input = "... your data ...";

var valueNames = new [] 
{
    "behavior_capture_widget:", 
    "customer_session_data:", 
    "customer_cookie_data:"
};

var items = input.Split(valueNames, StringSplitOptions.RemoveEmptyEntries);

Now you can extract your values:

var behaviorCaptureWidget = items[1].Trim();
var customerSessionData= items[2].Trim();
var customerCookieData= items[3].Trim().Replace("\"}", "");

Note the last one needs the trailing "} to be manually removed.

Answer 2

If you do not know the name of the keys in the key: value pairs before execution, or you do not know the order of the expected keys, you could use a regular expression and a dictionary to store any key-value pair:

class StrangeParser
{
    public static readonly Regex LINE_REGEX = new Regex("^\\s*([a-zA-Z0-9_]+)\\s*\\:\\s*\"(.*)\"\\s*$", RegexOptions.Multiline);
    public static Dictionary<string, string> ParseStr(string str)
    {
        var m = LINE_REGEX.Matches(str);
        var res = new Dictionary<string, string>();
        foreach (Match item in m)
        {
            res.Add(item.Groups[1].Value, item.Groups[2].Value);
        }
        return res;
    }

    static void Main(string[] args)
    {
        foreach (var item in ParseStr(@"
{
    behavior_capture_widget: ""<div id=""ndwc""><noscript><input type=""hidden"" id=""ndpd-spbd"" name=""ndpd-spbd""                            value=""ndpds~~~2.4177.112540pPaGJYVmt5WCtndGlUiUcRt3aSOPQ,,""></noscript></div> <script type=""text/javascript""></script>""
    customer_session_data:   ""2.4177.112540.1399312572.2.mFDzrW_JJeu-C_H45O5ADQ""
    customer_cookie_data:    ""2.4177.112540.1399312572.2.XYjAsjFsOVHFXBGNnnHc-g,,.""
}
"))
        {
            Console.WriteLine(item.Key + " " + item.Value);
        }
    }
}

Answer 3

If that is JSON always. I believe it is better to use " Json.NET ":

string json = @"{
  {
       behavior_capture_widget: "<div id=\"ndwc\"><noscript><input type=\"hidden\" id=\"ndpd-spbd" name=\"ndpd-spbd\"                            value=\"ndpds~~~2.4177.112540pPaGJYVmt5WCtndGlUiUcRt3aSOPQ,,\"></noscript></div> <script type=\"text/javascript\"></script>"
       customer_session_data:   "2.4177.112540.1399312572.2.mFDzrW_JJeu-C_H45O5ADQ"
       customer_cookie_data:    "2.4177.112540.1399312572.2.XYjAsjFsOVHFXBGNnnHc-g,,."

 }";

Dictionary<string, string> dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);

var mydata = dict["customer_cookie_data"]; // extraction

See at here

Answer 4

If you're going to be working with this format extensively, it may be worth it to design a parser for this syntax.

This can be done using parser combinators to define a syntax tree.

Using Sprache , I built this parser that gives you a Dictionary<string, string> :

var key = Parse.CharExcept(c => char.IsWhiteSpace(c) || c == ':', "").Many().Text();

var value =
    from leading in Parse.Char('"')
    from val in Parse.AnyChar.Until(Parse.Char('"').Then(_ => Parse.LineEnd)).Text()
    select val;

var separator =
    from x in Parse.WhiteSpace.Many()
    from colon in Parse.Char(':')
    from y in Parse.WhiteSpace.Many()
    select colon;

var keyValue =
    from k in key
    from s in separator
    from v in value
    select new KeyValuePair<string, string>(k, v);

var parser =
    from open in Parse.Char('{').Then(_ => Parse.WhiteSpace.Many())
    from kvs in keyValue.DelimitedBy(Parse.WhiteSpace.Many())
    from close in Parse.WhiteSpace.Many().Then(_ => Parse.Char('}'))
    select kvs.ToDictionary(kv => kv.Key, kv => kv.Value);

You can now use this parser like this:

var dictionary = parser.Parse(input);