Sorting Variables of Multidimensional Arrays
I have an array of integers: d []. for example (7 columns and multiple rows):
4 1 8 0 3 2 6
7 0 4 9 1 1 5
0 6 1 3 5 2 0
etc. At compile time, I don't know how many columns array d has. And I don't know at compile time which columns to use for orderby.
For example, you need to sort by: d [5], d [2], d [0], d [3]. But at runtime, I know the sort order of the columns. For example, the column indices are: 5, 2, 0, 3, which means columns d [5], d [2], d [0], d [3]. How can I order the array d using these column indices?
a source to share
Assuming you are using a jagged array ( int[][]
), you can use LINQ by concatenating OrderBy
and ThenBy
:
using System;
using System.Collections.Generic;
using System.Linq;
static class Program
{
static void Main()
{
int[][] data = {
new[]{4,1,8,0,3,2,6},
new[]{7,0,4,9,1,1,5},
new[]{0,6,1,3,5,2,0}};
int[] sortCols = { 5, 2, 0, 3 };
IEnumerable<int[]> qry = data;
if (sortCols.Length > 0)
{
IOrderedEnumerable<int[]> sorted =
qry.OrderBy(row => row[sortCols[0]]);
for (int i = 1; i < sortCols.Length; i++)
{
int col = sortCols[i]; // for capture
sorted = sorted.ThenBy(row => row[col]);
}
qry = sorted;
}
// show results (does actual sort when we enumerate)
foreach (int[] row in qry)
{
foreach (int cell in row)
{
Console.Write(cell);
Console.Write('\t');
}
Console.WriteLine();
}
}
}
You can also (alternatively) build a comparison to navigate to Array.Sort
.
a source to share