Using LINQ to Obtain Max of Columns for Two Dimensional Arrays

Is there anyway to use LINQ to obtain the maximum of each columns for two dimensional arrays?

Assume that I have the following:

var arrays = new double[5,100]();

I want to get the maximum of arrays[0,:], arrays[1,:] .... arrays开发者_StackOverflow[4,:]. How to use LINQ to do it?

I could have use such method

public double GetMax(double[,] arr, int rowIndex)
{
   var colCount = arr.GetLength(1);
   double max = 0.0;
   for(int i=0; i<colCount; i++)
   {
      max=Math.Max(Math.Abs(arr[rowIndex, i]), max);
   }
   return max;
}

But I would prefer a more succinct ways of doing things.

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I suppose you could always use Enumerable.Range as a compact form of indexed access:

public static double GetMax(double[,] arr, int rowIndex)
{
    return (from col in Enumerable.Range(0, arr.GetLength(1))
            select arr[rowIndex, col]).Max();
}

And if you want to get this for all rows:

public static double[] GetMaxForAllRows(double[,] arr, int rowIndex)
{
    return (from row in Enumerable.Range(0, arr.GetLength(0))
            let cols = Enumerable.Range(0, arr.GetLength(1))
            select cols.Max(col => arr[row, col])).ToArray();
}

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I don't think there is a built-in way to get a row from a multidimensional array. You can write an extension method though:

public static IEnumerable<T> Row<T>(this T[,] array, int rowIndex)
{
    var colCount = array.GetLength(1);
    for(int i=0; i<colCount; i++)
    {
        yield return arr[rowIndex, i];
    }
}

And then just use "normal" LINQ:

var max = array.Row(i).Max();

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LINQ does not have any methods that cover multi-dimensional arrays.

However, if you can convert it to a list, or maybe roll-your own extensions.

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You can use nested "from" statements. Thus iterate through the entire array with range variables representing the respective col/row position within the table. For each of the numbers, you wish to check if it a new max within its row or within its column.