How do I extract a string out of a string in c#

Question

I have the following string:

FirstName=John&LastName=Doe&City=London&ConfirmationId=WXASL320330

I want to extract the confirmationId from it. I have done a split on it and passed in the & character, but this returns ConfirmationId=WXASL320330 and I just WXASL320330. What is the best way of doing this?

The string is actually part of a property called RawProcessorResult that PayPal returns.

Answer 1

Another split on '='

Answer 2

Use a regular expression:

new Regex( @"ConfimationId=(\w+)" )

Answer 3

You can use Regular Expressions to get there.

Alternatively, you could just split your current result on =, and take the second argument.

string temp = "ConfirmationId=WXASL320330";
string[] portions = temp.Split("=");
string answer = portions[1];

Answer 4

You can do a split on that result and grab the confirmation number.

Answer 5

input.Split('&').Select(x => x.Split('=')).Single(x => x[0].Equals("ConfirmationId"))[1]

Answer 6

I would use a regex. ex:ConfirmationId=(\w{11})

Answer 7

You can do the following:

myString.Split('&')[3].Split('=')[1];

But a better way would probably be to use RegEx:

new RegEx("ConfirmationId=?*")

Answer 8

It depends. If that's part of your url in an asp.net app then you just want Request["Confirmationid"]. If it's from something else then use a regular expresion:

ConfirmationId={[^&]*}

Answer 9

You have three main ways of doing it.

var source = "FirstName=John&LastName=Doe&City=London&ConfirmationId=WXASL320330";
var parts = source.Split(new string[] { "&" }, StringSplitOptions.None);

Split again

var ids = parts[3].Split(new string[] { "=" }, StringSplitOptions.None);
var confirmationId = ids[1];

Substring with IndexOf

var confirmationId = parts[3].Substring(parts[3].IndexOf("="));

Regex

var pattern = new Regex("[^=]+=(?<value>.*)");
var match = pattern.Match(parts[3]);
var confirmationId = match.Groups["value"].Value;

Answer 10

I suggest using a regular expression.

String input =
   "FirstName=John&LastName=Doe&City=London&ConfirmationId=WXASL320330";

String confimationId =
   new Regex(@"ConfirmationId=(?<Id>[A-Z0-9]+)(&|$)").
   Match(input).
   Group("Id").
   Value;

If the confirmation id has more structure - for example allways 5 letters and 6 digits - you should include this information into the expression.

@"ConfirmationId=(?<Id>[A-Z]{5}[0-9]{6})(&|$)"

If the exact structure is not known or may change, just get everything up to the next ampersand.

@"ConfirmationId=(?<Id>[^&]+)"

Answer 11

string confirmationId = Regex.Match(input, @"(?<=ConfirmationId=)[^&]*").Value;

Answer 12

Is this a querystring in a URL? Are you using a web project? If so, there are built in methods for retrieving the values. Let me know if this is what you are doing and I'll post code.

Answer 13

The easiest way is to use the built-in HttpUtility.ParseQueryString() method:

string queryString = "FirstName=John&LastName=Doe&City=London&ConfirmationId=WXASL320330";

string confirmationID = 
  System.Web.HttpUtility.ParseQueryString(queryString)["ConfirmationId"]; 
  // returns "WXASL320330"

Answer 14

I think this is part of a Web Application, please try to use internal methods get around this, If some one the location of the Keys and their respective value changes, the you will get in to trouble.

Answer 15

I think the best way is to do is using the string indexes. Make sure you take into account if for some reason the specific string isn't there:

string val = "FirstName=John&LastName=Doe&City=London&ConfirmationId=WXASL320330";
string result = string.Empty;
if (val.LastIndexOf("ConfirmationId=")!= -1)
{
    string val2 = val.Substring(val.LastIndexOf("ConfirmationId=") + 15);
    result = (val2.IndexOf('&') != -1) ? val2.Substring(0, val2.IndexOf('&')) : val2;
}