如何从这个以逗号分隔的单行文件制作2D数组？

Question

I am trying to figure out how to turn the following, one-line CSV file into a 30x30 2D array.

http://pastebin.com/8NP7s7N0

I've tried looking it up myself, but I just can't seem to wrap my brain around the concept of multidimensional arrays, and I don't know how to turn a one-line file like this into an array of a specified size.

I want to be able to make an array that would look like this when printed:

0,0 = 2

0,1 = 2

All the way to 30,30.

Most of the numbers in the CSV are indeed 2's, but some are 1s. The difference is very important though. I am trying to make collision detection for a game, and this CSV file is the map. All I need left is how to create this array - leave the rest to me. :)

Thank you very much to all, have a nice day.

Answer 1

well, first you need to get the numbers...

var numbers = Read_File_As_String().Split(new char[',']).Select(n => int.Parse(n)).ToList();

then, you need to build your array

const int ROWS = 30;
const int COLS = 30;

var result = new int[ROWS, COLS];

for (int row = 0; row < ROWS; row++)
    for (int col = 0; col < COLS; col++)
        result[row, col] = numbers[(row * COLS) + col];

Answer 2

Assuming your file is 900 elements first you need to read it in..

something along the lines of

line = myStreamReader.readLine().Split(',') .. then in John U's example, value would be the next index in this array called line

I'll let you work out whats missing from my example :P

Answer 3

for(row=0;row<30;row++)
{
    for(col=0;col<30;col++)
    {
       array[row][col] = value;
    }
}

Value would need to be moved along to point to the next thing each time, but I'm sure you can figure that out.

Edited to add: If it's a map it might be easier to store it as an array in the first place.

Answer 4

Since you asked about the concept of multi-dimensional arrays, here are some useful ways of thinking about arrays. Please note these are analogies, meant to help you visualize them.

Think of a 1D array as a list of items (not in the programming sense of list!).

Think of a 2D array as a table (again, not in the programming sense!). In a table (like a spreadsheet) you have rows and columns, and each dimension in your array accesses one of these.

For higher dimensional arrays, it may help to think geometrically. For instance, you can think of 3D arrays as 3-dimensional points in space, and 4D arrays as 4-dimensional points in space-time.

So if you have a single CSV file, start off by conceptualizing how this would be re-structured as a table. Once you have that, you have a pretty straight-forward mapping to the array.

Answer 5

This should be a complete example using a 5 x 5 grid. I've tried it and seems to work as expected:

namespace ConsoleApplication1
{
    using System;

    class Program
    {
        const int MapRows = 5;
        const int MapColumns = 5;

        static void Main(string[] args)
        {
            // Create map and the raw data (from file)
            var map = new int[MapRows, MapColumns];
            string rawMapData = "1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25";
            string[] splitData = rawMapData.Split(',');
            int index = 0;

            // Loop through data
            for (int row = 0; row < MapRows; row++)
            {
                for (int column = 0; column < MapColumns; column++)
                {
                    // Store in map and show some debug
                    map[row, column] = int.Parse(splitData[index++]);
                    Console.WriteLine(string.Format("{0},{1} = {2}", row, column, map[row, column]));
                }
            }

            // Wait for user to read
            Console.ReadKey();
        }
    }
}