C# Transpose a 2D matrix, looking for the best way

Question

Hello,
What is the best and easiest way to transform a matrix?
With C# .NET4.8

// The best is with a sample i.e. --> Transpose the matrix from 3,5 to 5,3  
  
namespace WindowsFormsAppMatrixBasic.Core  
{  
    public static class ArrayExtensions  
    {  
        public static T[][] Transpose<T>(this T[][] source)  
        {  
            if (source.Length == 0 || source[0].Length == 0)  
            {  
                return Array.Empty<T[]>();  
            }  
  
            int rows = source.Length;  
            int cols = source[0].Length; // ???  
  
            T[][] result = new T[cols][];  
  
            for (int i = 0; i < cols; i++)  
            {  
                result[i] = new T[rows];  
  
                for (int j = 0; j < rows; j++)  
                {  
                    result[i][j] = source[j][i];  
                }  
            }  
            return result;  
        }  
    }  
  
  
    public class MatrixTest  
    {  
        public void TestMatrix()  
        {  
            List<string> data = new List<string> {  
    "0000",  
    "0000",  
    "0000",  
    "FFFF",  
    "0000",  
    "0000",  
    "0000",  
    "0000",  
    "0000",  
    "0000",  
    "0000",  
    "0000",  
    "FFFF",  
    "0000",  
    "0000"  
};  
  
// ****** From a list, I should make a matrix depend of x and y values.  
// Row	Col	x	y	State	Counter	Coding  
// 1	1	1	10	10	1	32321	0000  
// 2	2	1	20	10	1	32322	0000  
// 3	3	1	30	10	1	32323	0000  
// 4	4	1	40	10	0	32324	FFFF  
// 5	5	1	50	10	1	32325	0000  
  
// 6	1	2	10	110	1	32326	0000  
// 7	2	2	20	110	1	32327	0000  
// 8	3	2	30	110	1	32328	0000  
// 9	4	2	40	110	1	32329	0000  
// 10	5	2	50	110	1	32330	0000  
  
// 11	1	3	10	210	1	32331	0000  
// 12	2	3	20	210	1	32332	0000  
// 13	3	3	30	210	0	32333	FFFF  
// 14	4	3	40	210	1	32334	0000  
// 15	5	3	50	210	1	32335	0000  
  
  
            string[,] matrix = new string[,]  
{  
    {"0000", "0000", "0000", "FFFF", "0000"},  
    {"0000", "0000", "0000", "0000", "0000"},  
    {"0000", "0000", "FFFF", "0000", "0000"}  
};  
  
  
	// Transpose the matrix from 3,5 to 5,3  
	string[,] transposed = matrix.Transpose()  // ****** not work, however?  

https://files.fm/f/ufs626uwf

Answer 1

Hi @Markus Freitag ,
I tried your code, it should be the problem that the format does not correspond, you can try the following code.

namespace WindowsFormsApp1.Core  
{  
    public class ArrayExtensions<T>  
    {  
        public static T[,] Transpose(T[,] matrix)  
        {  
            var rows = matrix.GetLength(0);  
            var columns = matrix.GetLength(1);  
  
            var result = new T[columns, rows];  
  
            for (var c = 0; c < columns; c++)  
            {  
                for (var r = 0; r < rows; r++)  
                {  
                    result[c, r] = matrix[r, c];  
                }  
            }      
            return result;  
        }  
    }          
    public class MatrixTest  
    {  
        public void TestMatrix()  
        {  
            string[,] matrix = new string[3,5]  
            {  
                {"0000", "0000", "0000", "FFFF", "0000"},  
                {"0000", "0000", "0000", "0000", "0000"},  
                {"0000", "0000", "FFFF", "0000", "0000"}  
            };  
            var tMatrix = ArrayExtensions<string>.Transpose(matrix);  
            Console.WriteLine(tMatrix);  
        }  
    }  
}  

Edit:
File path:C:***\WindowsFormsApp1\bin\Debug\text.txt

public class MatrixTest  
    {  
        public void TestMatrix()  
        {  
            string[,] matrix = new string[3,5]  
            {  
                {"0000", "0000", "0000", "FFFF", "0000"},  
                {"0000", "0000", "0000", "0000", "0000"},  
                {"0000", "0000", "FFFF", "0000", "0000"}  
            };  
          //  var tMatrix = ArrayExtensions<string>.Transpose(matrix);  
            var rows = matrix.GetLength(0);  
            var columns = matrix.GetLength(1);  
            using (TextWriter tw = new StreamWriter("text.txt"))  
            {  
                tw.WriteLine("Original Matrix");  
                for (int i = 0; i < rows; i++)  
                {  
                    for (int j = 0; j < columns; j++)  
                    {  
                        tw.Write(matrix[i, j] + " ");  
                    }  
                    tw.WriteLine();  
                }  
                tw.WriteLine("Transpose Matrix");  
                for (int j = 0; j < columns; j++)  
                {  
                    for (int i = 0; i < rows; i++)  
                    {  
                        tw.Write(matrix[i, j] + " ");  
                    }  
                    tw.WriteLine();  
                }                  
            }  
        }  
    }  

Best regards,
Lan Huang

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Answer 2

what is wrong with the result? the code and debug values look correct.

 {
     {"0000", "0000", "0000", "FFFF", "0000"},
     {"0000", "0000", "0000", "0000", "0000"},
     {"0000", "0000", "FFFF", "0000", "0000"}
 }

//transposed:

 {
     {"0000", "0000", "0000"},
     {"0000", "0000", "0000"},
     {"0000", "0000", "FFFF"},
     {"FFFF", "0000", "0000"},
     {"0000", "0000", "0000"}
 }

Answer 3

Hi I tried the following way , which worked for me,

static void Main(string[] args)
        {
            List<string> strArr = new List<string> { "RC1", "RC2", "RC3", 				   "RC4" };
            List<string> strArr2 = new List<string> { "RC5", "RC6", "RC7", "RC8" };
            List<string> strArr3 = new List<string> { "RC9", "RC10", "RC11", "RC12" };
            int columnCount = strArr.Count;
            List<List<string>> lsResult = new List<List<string>>();
            List<List<string>> lstStrs = new List<List<string>>() { strArr,strArr2,strArr3 };
            for (int i = 0; i < columnCount; i++)
            {
                List<string> lstTemp = new List<string>();
                for (int j = lstStrs.Count -1; j >=0; j--)
                {
                    var temp = lstStrs[j];
                    lstTemp.Add(temp[i]);   
                    
                }
                lsResult.Add(lstTemp);
            }

            foreach (var lstStr in lsResult)
            {
                foreach (var str in lstStr)
                {

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