You could check tokens.Length and then act accordingly.
Should also advise you to use the generic List<> type instead of ArrayList.

This is an odd task. As danny pointed out the generic list is definetly the way to go! You could do something like this:

C# Syntax (Toggle Plain Text)

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
 
namespace daniweb
{
  public partial class frmWeirdHomework : Form
  {
    public frmWeirdHomework()
    {
      InitializeComponent();
    }
 
    private static string[] GetSampleData()
    {
      List<string> sl = new List<string>();
      sl.Add("1 2 3");
      sl.Add("3 4 5");
      sl.Add("6 7 8");
      sl.Add("");
      sl.Add("1 2 ");
      sl.Add("3 4 ");
      return sl.ToArray();
    }
 
    private static bool IsNumericArray(string[] arr)
    {
      if ((arr == null) || (arr.Length == 0))
        return false;
 
      int i;
 
      foreach (string s in arr)
      {
        if (!int.TryParse(s, out i))
          return false;
      }
      return true;
    }
 
    private void button2_Click(object sender, EventArgs e)
    {
      //string[] data = File.ReadAllLines(@"C:\yourfile.txt");
      string[] data = GetSampleData();
      List<List<int>> lstAllItems = new List<List<int>>(); //master list
 
      List<List<int>> workingSet = new List<List<int>>(); //holds our working lists until the format changes
 
      foreach (string line in data)
      {
        if (string.IsNullOrEmpty(line))
          continue;
        string[] sVals = line.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
        if (!IsNumericArray(sVals))
          continue;
 
        int[] iVals = Array.ConvertAll<string, int>(sVals, Convert.ToInt32);
        if (workingSet.Count != iVals.Length) //our format changed
        {
          lstAllItems.AddRange(workingSet.ToArray());
          workingSet.Clear();
          for (int i1 = 0; i1 < iVals.Length; i1++)
          {
            workingSet.Add(new List<int>());
          }
        }
        for (int i1 = 0; i1 < iVals.Length; i1++)
        {
          workingSet[i1].Add(iVals[i1]);
        }
      }
      if (workingSet.Count != 0)
        lstAllItems.AddRange(workingSet.ToArray());
 
 
      for (int i1 = 0; i1 < lstAllItems.Count; i1++)
      {
        List<int> lst = lstAllItems[i1];
        Console.WriteLine("Array[{0:F0}]: {1}", i1, string.Join(", ", lst.ConvertAll<string>(Convert.ToString).ToArray()));
      }
    }
 
  }
}

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.IO; namespace daniweb { public partial class frmWeirdHomework : Form { public frmWeirdHomework() { InitializeComponent(); } private static string[] GetSampleData() { List<string> sl = new List<string>(); sl.Add("1 2 3"); sl.Add("3 4 5"); sl.Add("6 7 8"); sl.Add(""); sl.Add("1 2 "); sl.Add("3 4 "); return sl.ToArray(); } private static bool IsNumericArray(string[] arr) { if ((arr == null) || (arr.Length == 0)) return false; int i; foreach (string s in arr) { if (!int.TryParse(s, out i)) return false; } return true; } private void button2_Click(object sender, EventArgs e) { //string[] data = File.ReadAllLines(@"C:\yourfile.txt"); string[] data = GetSampleData(); List<List<int>> lstAllItems = new List<List<int>>(); //master list List<List<int>> workingSet = new List<List<int>>(); //holds our working lists until the format changes foreach (string line in data) { if (string.IsNullOrEmpty(line)) continue; string[] sVals = line.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries); if (!IsNumericArray(sVals)) continue; int[] iVals = Array.ConvertAll<string, int>(sVals, Convert.ToInt32); if (workingSet.Count != iVals.Length) //our format changed { lstAllItems.AddRange(workingSet.ToArray()); workingSet.Clear(); for (int i1 = 0; i1 < iVals.Length; i1++) { workingSet.Add(new List<int>()); } } for (int i1 = 0; i1 < iVals.Length; i1++) { workingSet[i1].Add(iVals[i1]); } } if (workingSet.Count != 0) lstAllItems.AddRange(workingSet.ToArray()); for (int i1 = 0; i1 < lstAllItems.Count; i1++) { List<int> lst = lstAllItems[i1]; Console.WriteLine("Array[{0:F0}]: {1}", i1, string.Join(", ", lst.ConvertAll<string>(Convert.ToString).ToArray())); } } } }

text Syntax (Toggle Plain Text)

Array[0]: 1, 3, 6
Array[1]: 2, 4, 7
Array[2]: 3, 5, 8
Array[3]: 1, 3
Array[4]: 2, 4

Array[0]: 1, 3, 6 Array[1]: 2, 4, 7 Array[2]: 3, 5, 8 Array[3]: 1, 3 Array[4]: 2, 4

I'm sure you can figure out how to make 0->A, 1->B, etc

Hello.
Both ArrayList and List classes are provided to work with dynamic arrays. But, in ArrayList all elements have type of System.Object. And in List you specify the type of elements by yourself. Let's see what it gives to you:

1. Suppose, you have an array of strings.
For ArrayList: while adding new element to array - it will be
cast to an Object type and then added to list. Then to take the
value of it - you'd have to cast it back to String.

c# Syntax (Toggle Plain Text)

            ArrayList list = new ArrayList();
            list.Add("String element");
 
            string element = (string)list[0];

ArrayList list = new ArrayList(); list.Add("String element"); string element = (string)list[0];

For List: you're just define a List of strings and there's no need
in boxing/unboxing operations (casting to Object type and back).

c# Syntax (Toggle Plain Text)

            List<string> otherList = new List<string>();
            otherList.Add("String element");
            string otherElement = otherList[0];

List<string> otherList = new List<string>(); otherList.Add("String element"); string otherElement = otherList[0];

2. Since the every reference type can be cast to System.Object and every value type can be boxed into an Object, it's possible to have something like this (in ArrayList):

c# Syntax (Toggle Plain Text)

ArrayList list = new ArrayList();
            list.Add("String element");
            list.Add(2);

ArrayList list = new ArrayList(); list.Add("String element"); list.Add(2);

The List<T> is strong-typed, so it's one more advantage. E.g. it wouldn't allow you to add Integer in your list of Strings. You will be warned at compilation time that you're trying to do something illegal.

c# Syntax (Toggle Plain Text)

            List<string> otherList = new List<string>();
            otherList.Add("String element");
            otherList.Add(2); // compilation time error

List<string> otherList = new List<string>(); otherList.Add("String element"); otherList.Add(2); // compilation time error

3. And here's a nice post, where performance of List And ArrayList was compared: ArrayList’s vs. generic List for primitive types and 64-bits