How do I sort jagged array by row in C#?

陌路散爱 提交于 2021-02-07 12:28:29

问题


I have 2D jagged array. And I want to sort it by any rows.

I've searched and found code for sorting by columns

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])); 
}

Can I adapt it for sort by any rows ?

Any help is appreciated.

Sample of my jagged array (Added)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = 10;
            int[][] capm = new int[3][];
            for (int i = 0; i <= 2; i++)
            {
                capm[i] = new int[n + 1];
            }
            Random rand = new Random();            
            for (int i = 1; i <= n; i++)
            {
                capm[1][i] = i;
            }

            for (int i = 1; i <= n; i++)
            {
                capm[2][i] = rand.Next(1, 6);
            }

            Sort(capm, 2);

            Console.ReadLine();
        }
            private static void Sort<T>(T[][] data, int col)    
            {  
                data = data.OrderBy(i => i[col]).ToArray();
            }
        }

    }

@Dani & @Martin I want my jagged array to sort by capm[2][].


回答1:


The only way I can think of doing this is sorting by an array of indices:

private static void Sort<T>(T[][] data, int row) 
{
    int[] Indices = new int[data[0].Length];
    for(int i = 0; i < Indices.Length; i++)
        Indices[i] = i;

    Comparer<T> comparer = Comparer<T>.Default;
    Array.Sort(Indices, (x, y) => comparer.Compare(data[row][x], data[row][y]);

    for(int i = 0; i < data.Length; i++)
    {
        T[] OldRow = (T[])data[i].Clone();
        for(int j = 0; j < OldRow.Length; j++)
            data[i][j] = OldRow[i][Indices[j]];
    }
}



回答2:


Given you are using a jagged array this will sort it by the 3rd item.. but a 2D array is probably better if you want to guarantee that each row has the same number of columns... If you have an array within the array which doesn't have a 3rd column, this will fail!

private static void Sort<T>(T[][] data, int col)    
{  
    data = data.OrderBy(i => i[col]).ToArray();
}

Edit:

In order to do anything with the new data reference you either need to return it or pass the parameter by reference:

private static void Sort<T>(ref T[][] data, int col)    
{  
    data = data.OrderBy(i => i[col]).ToArray();
}

The array itself isn't sorted, a new sorted array is created



来源:https://stackoverflow.com/questions/8162348/how-do-i-sort-jagged-array-by-row-in-c

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