# Convert python numpy 2D array to matlab 2D array

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Manju gurik on 22 Feb 2022
Commented: Manju gurik on 24 Feb 2022
Hi,
i am calling python function which returns numpy 2D array in this fashion.
data = [ [10, 20, 30, 40], [100, 200], [10, 40, 50, 80, 90, [10, 00, 88, 99, 199, 100]]
when i try converting into matlab array
mat_array = double(data)
its giving me error
Error using py.numpy.ndarray/double
Conversion of Python 'ndarray' type to MATLAB 'double' is only supported for real numbers and logicals.
But when i have 1D numpy array
data_1 = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500]
double(data_1)
This works.
Can you please guide me on converting python numpy 2D array to matlab array

Sean de Wolski on 23 Feb 2022
Edited: Sean de Wolski on 23 Feb 2022
What is the underlying python class of your ndarray? It doesn't seem to be recognized by double. Here, I create it with int8 and that works with double and int8 in MATLAB. Look at the display to see the hint or post back with more details
>> nd = py.numpy.zeros_like(int8(magic(4)))
nd =
Python ndarray:
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
Use details function to view the properties of the Python object.
Use int8 function to convert to a MATLAB array.
>> double(nd)
ans =
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
>> int8(nd)
ans =
4×4 int8 matrix
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
Sean de Wolski on 24 Feb 2022
Using gRPC through python or .NET seems perfectly logical to me. You'll just need a little data massaging after getting it back. I think I'd recommend going to the NaN-delimited segments approach, e.g. getting the ndarray you have into:
[1.2 2.3 nan 3.4 23 2.3 nan 1 1 1 1 1]
Manju gurik on 24 Feb 2022
Ok. Got it. Thank you.
I understand that we dont have one available for matlab directly to connect to grpc services without Python or .NET.