Create 2D array from txt file

Question

Okay so I've managed to read in a .txt file... now I'm trying to figure the best way to convert this information into a 2D array.

My text file (first two number provide height and width):

5
5
0,0,0,0,0
0,0,0,0,0
0,0,1,0,0
0,1,1,1,0
1,1,1,1,1

My C# / XNA:

string fileContents = string.Empty;
try
{
    using (StreamReader reader = new StreamReader("Content/map.txt"))
    {
        fileContents = reader.ReadToEnd().ToString();
    }
}
catch (Exception e)
{
    Console.WriteLine(e.Message);
}

Now what I need to do next is define the size of the 2-dimensional map array and then populate the entry values... this is where I'm getting a bit stuck and have found various ways I can loop through the data but I don't think any of them have been terribly tidy.

What I've tried to do is have one loops which splits by newline... and then another loop which splits by comma delimiter.

Is this the best way to do it... or are there better alternatives?

Sounds like you are on the right track. Perhaps try to use the extension methods e.g ToArray() — Tom
– Tom, Commented Mar 12, 2012 at 20:45

Henk Holterman · Accepted Answer · 2012-03-12 21:45:02Z

5

It can be done with LINQ but that is only practical when you want (accept) an array-of-array, int[][] instead of a straight 2-dimensional int[,] .

int[][] data = 
    File.ReadLines(fileName)
    .Skip(2)
    .Select(l => l.Split(',').Select(n => int.Parse(n)).ToArray())
    .ToArray();

answered Mar 12, 2012 at 21:45

Henk Holterman

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5 Comments

diggersworld Over a year ago

Is this what is referred to as "jagged" arrays?

Henk Holterman Over a year ago

Yes, but I prefer array of arrays

Henk Holterman Over a year ago

PS: I'm not sure if all this (ReadLines) is available in XNA. Missed that tag.

diggersworld Over a year ago

There's Readline() which does them one by one I think. I haven't come across a plural version though.

Henk Holterman Over a year ago

And System.IO.File.ReadAllLines() ?

JohnB · Accepted Answer · 2012-03-12 21:13:45Z

0

The code below doesn't require the first to rows in your sample .CSV file:

5
5

I'd prefer it this way, but as a consequence, the code below reads the file twice. It would take a small modification use the first two rows in your sample instead.

private int[,] LoadData(string inputFilePath)
{
  int[,] data = null;

  if (File.Exists(inputFilePath))
  {
    Dictionary<string, int> counts = GetRowAndColumnCounts(inputFilePath);

    int rowCount = counts["row_count"];
    int columnCount = counts["column_count"];

    data = new int[rowCount, columnCount];

    using (StreamReader sr = File.OpenText(inputFilePath))
    {
      string s = "";
      string[] split = null;

      for (int i = 0; (s = sr.ReadLine()) != null; i++)
      {
        split = s.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);

        for (int j = 0; j < columnCount; j++)
        {
          data[i, j] = int.Parse(split[j]);
        }
      }
    }
  }
  else
  {
    throw new FileDoesNotExistException("Input file does not exist");
  }

  return data;
}

private Dictionary<string, int> GetRowAndColumnCounts(string inputFilePath)
{
  int rowCount = 0;
  int columnCount = 0;

  if (File.Exists(inputFilePath))
  {
    using (StreamReader sr = File.OpenText(inputFilePath))
    {
      string[] split = null;
      int lineCount = 0;

      for (string s = sr.ReadLine(); s != null; s = sr.ReadLine())
      {
        split = s.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);

        if (columnCount == 0)
        {
          columnCount = split.Length;
        }

        lineCount++;
      }

      rowCount = lineCount;
    }

    if (rowCount == 0 || columnCount == 0)
    {
      throw new FileEmptyException("No input data");
    }
  }
  else
  {
    throw new FileDoesNotExistException("Input file does not exist");
  }

  Dictionary<string, int> counts = new Dictionary<string, int>();

  counts.Add("row_count", rowCount);
  counts.Add("column_count", columnCount);

  return counts;
}

edited Mar 12, 2012 at 21:13

answered Mar 12, 2012 at 21:00

JohnB

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3 Comments

diggersworld Over a year ago

That looks a bit lengthy... check out my solution.

JohnB Over a year ago

Yes you made the modification that I mentioned. Putting height and width in the first 2 rows eliminates the need for the 2nd function. However, I don't like the format of the input file your way. It's a preference thing.

diggersworld Over a year ago

Mmmm... I can understand... once it gets big its hard to count the number of columns etc... so automation there would help.

diggersworld · Accepted Answer · 2012-03-12 21:39:35Z

Here's the solution I've come up with which appears to work.

int[,] txtmap;
int height = 0;
int width = 0;
string fileContents = string.Empty;

try
{
    using (StreamReader reader = new StreamReader("Content/map.txt"))
    {
        fileContents = reader.ReadToEnd().ToString();
    }
}
catch (Exception e)
{
    Console.WriteLine(e.Message);
}

string[] parts = fileContents.Split(new string[] { "\r\n" }, StringSplitOptions.None);
for (int i = 0; i < parts.Length; i++)
{
    if (i == 0)
    {
        // set width
        width = Int16.Parse(parts[i]);
    }
    else if (i == 1)
    {
        // set height
        height = Int16.Parse(parts[i]);

        txtmap = new int[width, height];
    }

    if (i > 1)
    {
        // loop through tiles and assign them as needed
        string[] tiles = parts[i].Split(new string[] { "," }, StringSplitOptions.None);
        for (int j = 0; j < tiles.Length; j++)
        {
            txtmap[i - 2, j] = Int16.Parse(tiles[j]);
        }
    }
}

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