C# Populate An Array with Values in a Loop

I would create a custom Item class and then populate a list, for easy access and sorting, with self contained items. something like:

 public Class MyItem
 {
     public int first { get; set; }
     public int second { get; set; }
     public float third { get; set; }

     public MyItem(int one, int two, float three)
     {
         this.first = one;
         this.second = two;
         this.third = three;
     }
}

then you could do:

List<MyItem> mylist = new List<MyItem>();

and then in your loop:

using (StreamReader file = new StreamReader("Score_4.dat"))            
{   
    while ((line = file.ReadLine()) != null && line.Length > 10)
    {                    
        line.Trim();
        string[] parts;
        parts = line.Split(' ');
        MyItem item = new Item(Int32.Parse(parts[0]),Int32.Parse(parts[1]),Float.Parse(parts[2]));
        mylist.Add(item);
        i++; 
    }
}

As there are numbers like 30.1 so int is not suitable for this, and also it must not be a double[] but double[][]:

string[] lines = File.ReadAllLines("file.txt");
double[][] array = lines.Select(x => s.Split(' ').Select(a => double.Parse(a)).ToArray()).ToArray();

Issue is that int array is single dimensional.

My suggestion is that you can put a class with 3 properties and populate a list of class there. It's better to have class with same property names that you require to build JSON. So that you can easily serialize this class to JSON using some nugets like Newtonsoft and make api calls easily.

Your int array is a single dimensional array yet you're trying to index it like a multidemensional array. It should be something like this:

intArray[i] = parts[0]

(However you'll need to handle converting to int for parts that are fractional)

Alternatively, if you want to use a multidimensional array, you have to declare one.

int[][] intArray = new int[*whatever your expected number of records are*][3]

Arrays have a static size. Since you're reading from a file and may not know how many records there are until your file finishes reading, I recommend using something like a List of Tuples or a Dictionary depending on your needs.

A dictionary will allow you to have quick lookup of your records without iterating over them by using a key value pair, so if you wanted your records to match up with their line numbers, you could do something like this:

Dictionary<int, int[]> test = new Dictionary<int, int[]>();
int lineCount = 1;
while ((line = file.ReadLine()) != null && line.Length > 10)
   {
      int[] intArray = new int[3];
      line.Trim();
      string[] parts = line.Split(' ');
      for (int i = 0; i < 3; i++)
          {
               intArray[i] = int.Parse(parts[i]);
          }
      test[lineCount] = intArray;
      lineCount++;

  }

This will let you access your values by line count like so:

test[3] = *third line of file*