Is there a better way to do this?

chobo2 · February 13th, 2009, 12:37 PM

Hi

I am doing some paypal stuff. PayPal returns big long string with values called NVP values.

they look like this

FIRSTNAME=Robert&MIDDLENAME=Herbert&LASTNAME=Moore

In one of the responses theoretically 40 fields can be returned as an array.

So It would look like something like this(in paypals api they have an array looking thing that can call indexes up by number or name)

["Firstname"] = Robert;

So I want to place all these variables in some properties so it is easier to grab and use these returned response fields.

so I probably have:

public static string FirstName { get; set;}

But not the problem is I don't know how to put them into these properties.

The only way I can think of is go through this how array and using a switch statement and start putting them where they belong but of course that will be pretty long switch statement.

The only other way I can think of is a big if/else statements but that is even worse.

Is there a better way?

gbianchi · February 13th, 2009, 01:07 PM

Hi there.. I will think in vb, but this obviously the same (with a little code change). You have a collection object that is can be accesed by key. What if you fill that collection using the parameter name as key and the value as value. This way, you avoid the if or select case.

Bob Bedell · February 14th, 2009, 01:02 AM

Seems like the trick wold be figuring out how to get an enumerator for the "array looking thing". Then you could just use a foreach statement to enumerate it, and load the key/value pairs into a Dictionary<TKey, TValue> or similar class.

For example, if you had a text file formatted like:

FIRSTNAME=Robert
MIDDLENAME=Herbert
LASTNAME=Moore

you could load a Dictionary with:

Code:

var nameValueList = newDictionary<string, string>();
foreach (var line inFile.ReadAllLines("ArrayLookingThing.txt")) // reads file from bin/debug
   nameValueList.Add(line.Split('=')[0], line.Split('=')[1]);
Console.WriteLine(nameValueList["FIRSTNAME"]);

File.ReadAllLines returns a string array which implements IEnumerable.

Just don't know enough about the data structure you're accessing. Can you iterate over it some how? Or maybe just parse the NVP string to a text file or other format that you can invoke an enumerator on, as above.

Bob

Bob Bedell · February 14th, 2009, 01:47 AM

Code:

classProgram
{
 staticvoid Main(string[] args)
 {
    var nameValueList = ParseNVPString  ("FIRSTNAME=Robert&MIDDLENAME=Herbert&LASTNAME=Moore");
    Console.WriteLine("{0} {1} {2}", nameValueList["FIRSTNAME"],
       nameValueList["MIDDLENAME"], 
       nameValueList["LASTNAME"]);
    Console.Read();
}
publicstaticDictionary<string, string> ParseNVPString(string NVPString) 
{
  string[] kayValuePairs = NVPString.Split('&');
  var nameValueList = newDictionary<string, string>();
  foreach (var keyValuePair in kayValuePairs)
  {
     nameValueList.Add(keyValuePair.Split('=')[0], keyValuePair.Split('=')[1]);
  }
  return nameValueList;
  }
}

Bob Bedell · February 16th, 2009, 09:14 PM

Just playing around with a LINQ to Objects version to:

Code:

staticvoid Main(string[] args)
{
  Dictionary<string, string> dictionary = 
              LinqParseNVPString("FIRSTNAME=Robert&MIDDLENAME=Herbert&LASTNAME=Moore");
 
  Console.WriteLine("{0} {1} {2}",
                     dictionary["FIRSTNAME"],
                     dictionary["MIDDLENAME"],
                     dictionary["LASTNAME"]);
  Console.Read();
}
public static Dictionary<string, string> LinqParseNVPString(string NVPString) 
{
  string[] keyValuePairs = NVPString.Split('&');
  Dictionary<string, string> dictionary = 
                               (from kvp in keyValuePairs
                               select new
                               {
                                  Key = kvp.Split('=')[0],
                                  Value = kvp.Split('=')[1]
                               }).ToDictionary(a => a.Key, a => a.Value);
  return dictionary;
}

Bob Bedell · February 16th, 2009, 09:42 PM

Here's the chained method call syntax instead of the query expression syntax:

Code:

publicstaticDictionary<string, string> LinqParseNVPString(string NVPString)
{
return NVPString.Split('&')
               .Select(k => new { Key = k.Split('=')[0], Value = k.Split('=')[1] })
                .ToDictionary(k => k.Key, k => k.Value);
}