How do I sort a two-dimensional (rectangular) array in C#?

Question

I have a two-dimensional array (of Strings) which make up my data table (of rows and columns). I want to sort this array by any column. I tried to find an algorithm for doing this in C#, but have not been successful.

Any help is appreciated.

Answer 1

Can I check - do you mean a rectangular array ([,])or a jagged array ([][])?

It is quite easy to sort a jagged array; I have a discussion on that here. Obviously in this case the Comparison<T> would involve a column instead of sorting by ordinal - but very similar.

Sorting a rectangular array is trickier... I'd probably be tempted to copy the data out into either a rectangular array or a List<T[]>, and sort there, then copy back.

Here's an example using a jagged array:

static void Main() {  // could just as easily be string...     int[][] data = new int[][] {          new int[] {1,2,3},          new int[] {2,3,4},          new int[] {2,4,1}      };      Sort<int>(data, 2);  }  private static void Sort<T>(T[][] data, int col)  {      Comparer<T> comparer = Comparer<T>.Default;     Array.Sort<T[]>(data, (x,y) => comparer.Compare(x[col],y[col]));  }  

For working with a rectangular array... well, here is some code to swap between the two on the fly...

static T[][] ToJagged<T>(this T[,] array) {     int height = array.GetLength(0), width = array.GetLength(1);     T[][] jagged = new T[height][];      for (int i = 0; i < height; i++)     {         T[] row = new T[width];         for (int j = 0; j < width; j++)         {             row[j] = array[i, j];         }         jagged[i] = row;     }     return jagged; } static T[,] ToRectangular<T>(this T[][] array) {     int height = array.Length, width = array[0].Length;     T[,] rect = new T[height, width];     for (int i = 0; i < height; i++)     {         T[] row = array[i];         for (int j = 0; j < width; j++)         {             rect[i, j] = row[j];         }     }     return rect; } // fill an existing rectangular array from a jagged array static void WriteRows<T>(this T[,] array, params T[][] rows) {     for (int i = 0; i < rows.Length; i++)     {         T[] row = rows[i];         for (int j = 0; j < row.Length; j++)         {             array[i, j] = row[j];         }     } }