c# lists not storing values after using int.TryParse

Question

I have the following code below that reads in text file and searches it for integers. I am using 'int.TryParse' to do this but it is not storing the integer values in the lists after it has run, just wondering if you could tell me what is wrong with this code. Thanks.

 namespace AccessErrorFile
  {
    class Program
    {
        static void Main(string[] args)
        {
            List<int> plans = new List<int>();
            List<int> events = new List<int>();

            using (var reader = new StreamReader(@"D:\Temp\AccessEmail.txt"))

                try
                {
                    string line;
                    while ((line = reader.ReadLine()) != null)
                    {
                        //split the line
                        string[] parts = line.Split(new[] { "Event" },      StringSplitOptions.None);

                        //get valid integers
                        plans.Add(GetInt(parts[0].Split(' ', '\'')));
                        events.Add(GetInt(parts[1].Split(' ', '\'')));                    
                   }
                }
                catch (System.Exception ex)
                {
                    Console.WriteLine("Error" + ex.Message);
                }

               //print the elements in the lists
               foreach (int x in plans)
               {
                   Console.WriteLine(x);
               }

               foreach (int y in events)
               {
                   Console.WriteLine(y);
               }

               //print the number of elements in the lists
               Console.WriteLine(plans.Count);
               Console.WriteLine(events.Count);
               Console.ReadLine();
        }    
        public static int GetInt(string[] a)
        {
            int i = 0;
            foreach (string s in a)
            int.TryParse(s, out i);    
            return i;
        }         
    }
}

Did you use your debugger to inspect what kind of values you're attempting to parse? How can we possibly tell you why TryParse is failing if you don't even tell us what it's attempting to parse? — tnw
– tnw, Commented Nov 6, 2014 at 17:50
Hi tnw, I am parsing lines like this in the text file: "Previous errors were for Plan id '1111111' Event id '33234042'" — John
– John, Commented Nov 6, 2014 at 18:05

Tigran · Accepted Answer · 2014-11-06 17:59:22Z

3

your problem is

  public static int GetInt(string[] a)
    {
        int i = 0;
        foreach (string s in a) //HERE
            int.TryParse(s, out i); //AND HERE 

        return i;
    }

you are parsing in the loop, so the return i statement returns basically the last s of iteration, which, most probably is not a number, so i=0.

If you want to add all numbers from the string to array of ints, you can do something like:

IEnumerable<int> GetNumbersFromList(string[] s) {

    foreach(var str in s) {
        int val;        
        if(int.TryParse(str, out val)) 
            yield return val;
    }
}

and after

  plans.AddRange(GetNumbersFromList(parts));

Just a basic idea, naturally, you have to fit it to your needs.

edited Nov 6, 2014 at 17:59

answered Nov 6, 2014 at 17:51

Tigran

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2 Comments

John Over a year ago

Hi Tigran, what would be the solution for this, it needs to loop like this I think as the line is in this format: "Previous errors were for Plan id '1111111' Event id '33234042'"

Tigran Over a year ago

@John: you create an array of string and feed it into the this function. it roll overs the array of string during iteration and generates ints available inside an array.

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