CODEWITHSUNDEEP
c#arrayssorting
akaBase
akaBase

Reputation: 2250

Sorting a list of 2D arrays

I'm trying to sort a list containing bool 2D arrays like below.

List<bool[,]>boolList;

bool[,] bool2DArray = {
    {true,true,true,true},
    {true,true,true,true},
    {true,true,true,true}
};

I've been trying to sort the list they're in by the amount of true counts within each 2D Array.

After some research and looking over Stack Overflow I haven't been able to find a solution for this specific issue; many of the solutions I was able to find wouldn't work for me in this situation where I'm not comparing them directly, but rather the result of a calculation on them which led me to trying with a Lambada type solution which also failed but I think that might have been due to me not understanding how to implement it correctly.

Edit

Simple function I made for getting the count

int GetCount(bool[,]bool2DArray) {
    int count = 0;
    int rows = bool2DArray.GetUpperBound(0);
    int columns = bool2DArray.GetUpperBound(1);


    for (int x = 0; x <= rows; x++) {
        for (int i = 0; i <= columns; i++) {
            bool isTrue = bool2DArray[x, i];

            if (isTrue) {
                count++;
            }
        }
    }
    return count;
}

And this is the Lambada type solution I think is in the right direction but isn't valid.

List<bool[,]> sortedList = boolList.Sort((a,b) => (GetCount(a).CompareTo(GetCount(b))));

Upvotes: 1

Views: 107

Answers (2)

Marco Salerno
Marco Salerno

Reputation: 5203

I prefer this approach which I think is more readable and cover more usecases:

class Program
{
    static void Main(string[] args)
    {
        List<bool[,]> boolList = new List<bool[,]>() {
        new bool[,] {
            {true,true,true,true},
            {true,true,true,true},
            {true,true,true,true}
        },
        new bool[,] {
            {false,true,true,true},
            {false,true,true,true},
            {false,true,true,true}
        }
        };

        boolList = OrderBoolArraysByBoolean(boolList, true);
    }

    private static List<bool[,]> OrderBoolArraysByBoolean(List<bool[,]> listOfArrays, bool value)
    {
        return listOfArrays.OrderByDescending(x => x.Cast<bool>().Count(i => i == value)).ToList();
    }
}

Upvotes: 0

Gilad Green
Gilad Green

Reputation: 37299

You'd first want to see how to easily work with the 2d array and count the number of trues in it. To do so for a single item, you could do something similar to what is found in this question: Fast way to convert a two dimensional array to a List ( one dimensional )

bool2DArray.Cast<bool>().Count(i => i)

Then wrapping that with OrderDescendingBy you get the desired result:

var collection = new List<bool[,]> { bool2DArray, ... };
var result = collection.OrderByDescending(item => item.Cast<bool>().Count(i => i));

Upvotes: 2

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