HOW to change NDArray to C#'s int[] about numpy.net HOT 4 CLOSED

I extended the documentation with an example:

Create a Numpy array from a C# array and vice versa

To work with data from C# in Numpy it has to be copied into the Python engine by using np.array(...). You get an NDarray that you can use for further processing of the data. Here we calculate the square root:

// create an NDarray from a C# array
var a = np.array(new[] { 2, 4, 9, 25 });
Console.WriteLine("a: "+ a.repr);
// a: array([ 2,  4,  9, 25])
// apply the square root to each element
var roots = np.sqrt(a);
Console.WriteLine(roots.repr);
// array([1.41421356, 2.        , 3.        , 5.        ])

After processing the data you can copy it back into a C# array use a.GetData<int>(), but be aware of the datatype of the NDarray in order to get correct values back:

// Copy the NDarray roots into a C# array from NDarray (incorrect datatype)
Console.WriteLine(string.Join(", ", roots.GetData<int>()));
// 1719614413, 1073127582, 0, 1073741824 
Console.WriteLine("roots.dtype: " + roots.dtype);
// roots.dtype: float64
Console.WriteLine(string.Join(", ", roots.GetData<double>()));
// 1.4142135623731, 2, 3, 5

from numpy.net.

How do we do this forint[,]?
I get Can not copy the data with data type due to limitations of Marshal.Copy: Int32[]

from numpy.net.

yeah, it doesn't work. you need to use int[] and calculate the index position yourself when accessing the data in c#. if you want help you can use my library SliceAndDice which allows you to reshape in c# and use like a numpy array.

from numpy.net.

https://github.com/henon/SliceAndDice

from numpy.net.