Converting a 2d array along with its elements from string to int

Question

As much as I tried to find a similar version in the question here, I couldn't find something.. so I am asking your help. After reading some numbers from a textfile (now in string format), I split them in rows and columns and add them to a 2d-array (in string format as well). Now I want to convert everythinh in integers so that I can play with sorting the numbers out later. Here is my code...

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using System.IO;

 namespace ArrayProgram
 {
   class Program
 {
    int number = 0;
    int i = 0;
    int k = 0;
    string strnum;


    public void onetohundredints()  
    {
        StreamWriter writer = new StreamWriter("numberstored.txt");

        for (i = 0; i < 10; i++)
        {

            for (k = 0; k < 10; k++)
            {
                number++;

                Console.Write(number + " ");
                strnum = number.ToString();  
                writer.Write(strnum + " ");
            }

            Console.WriteLine();
            writer.WriteLine();
        }
            writer.Close();
    }

    public void readints()
    {
        StreamReader reader = new StreamReader("numberstored.txt");
        string data = reader.ReadToEnd();
        reader.Close();

        string[,] dataarray = new string[10,10];
        int[] numbers = new int[100];

        string[] dataperlines = data.Split(new[] { '\r','\n' },StringSplitOptions.RemoveEmptyEntries);

        for(int i=0; i<=dataperlines.Count()-1; i++)
        {
            string[] numbersperrow = dataperlines[i].Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            for (int j=0; j<=numbersperrow.Count()-1; j++)
            {            
                dataarray[i, j] = numbersperrow[j];
            }
        }

    }


    public static void Main(string[] args) 
    {
        Program prog = new Program();
        prog.onetohundredints();
        prog.readints();
        Console.ReadKey();
    }
}
}

After I insert the number into the 2d-array, how do I convert all of it in integers?

Answer 1

I am happy to say that both solutions work. I now have my numbers in my 2d array. But now I wish to play with them. Let's say that I want the numbers printed on the screen in reverse order.

Having this correct solution:

        int numbers;
        int[,] dataarray = new int[10,10];
        string[] dataperlines = data.Split(new[] { '\r','\n' },StringSplitOptions.RemoveEmptyEntries);

        for(int i=0; i<=dataperlines.Count()-1; i++)
        {
            string[] numbersperrow = dataperlines[i].Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            for (int j=0; j<=numbersperrow.Count()-1; j++)
            {
                numbers = int.Parse(numbersperrow[j]);
                dataarray[i, j] = numbers;
                Console.Write(numbers + " ");
            }
            Console.WriteLine();
        }

I know that I have to make a double for loop. But how do I write a succesful syntax for the numbers to be printed properly? I also tried this:

int[,] reversedarray = new int[10, 10];
reversedarray[i, j] = Array.Reverse(dataarray[i,j]); 

but the dataarray[i,j] becomes red and the error "cannot convert from int to system.Array occurs... what am I missing?

I also tried this...

for (i = 10; i <= dataperlines.Count(); i--)
        {
            string[] numbersperrow = dataperlines[i].Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            for (j =10; j <= numbersperrow.Count(); j--)
            {
                numbers = int.Parse(numbersperrow[j]);
                reversedarray[i, j] = numbers;

                Console.Write(numbers + " ");
            }
            Console.WriteLine();
        }

But I have an IndexOutOfRange exception coming from

string[] numbersperrow = dataperlines[i].Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);

I understood that since I splitted the columns into rows too, it is unecessary to write it again, but I am stuck. I tried simplifying the code since I have my 2darray with its elements and I my tries were fallacious. Any more suggestions?

Answer 2

If you don't have a particular reason to have an array of strings, you can just save you data as int in the first place. Just change your inner for loop to do:

var parsed = int.TryParse(numbersperrow[j], out dataarray[i, j]);
if (!parsed)
{
    // Error
}

While that should work, I would suggest to re-write your ReadData method to look similar to the sample below.

public int[,] ReadData(string filePath, int xDimension, int yDimension)
{
    var results = new int[xDimension, yDimension];

    var lines = File.ReadLines(filePath);

    for (var i = 0; i < allLines.Count(); i++)
    {
        var values = lines[i].Split(new[] { ' ' }, 
                                    StringSplitOptions.RemoveEmptyEntries);

        for (var j = 0; j < values.Count(); j++)
        {
            var parsed = int.TryParse(values[j], out results[i, j]);
            if (!parsed) { }
        }
    }

    return results;
}

Answer 3

You're putting everything into a string array. That array can only hold strings, not numbers. If you want to make the 2d array hold numbers, define it as int[,] dataarray = new int[10,10]; Next, in the final loop, simply do dataarray[i, j] = Convert.ToInt32(numbersperrow[j]);

Edit: You can use int.TryParse(numbersperrow[j], out value) if you aren't sure that numbersperrow[j] will be a number. Value will return false if the conversion is not successful.