How do I convert matlab.double arrays to numpy arrays when using MATLAB Engine for Python?

When working in Python and using the MATLAB Engine API for Python, how can I efficiently convert the matlab.double arrays to numpy arrays?

Answer 1

[MathWorks Support Team]

There are a couple of ways to accomplish this. One method is to use numpy's built-in method, 'asarray':

Start by loading your matlab.double array:

myData = eng.eval("load('{}','cluster_class','par')".format('sampleData.mat'))

With MATLAB R2022a and later, you can convert matlab.double directly to a numpy array:

a = np.array(myData['cluster_class'])

To add additional specification, use MATLAB engine's functions to convert to a Python array with 'noncomplex()', then to a numpy array:

a = np.array(myData['cluster_class'].noncomplex().toarray(), 'int')

We use the 'noncomplex()' call to retrieve the data in 1D format (provided it's noncomplex; for complex data, we can use 'real()' and 'imag()' calls). We also offer the 'toarray()' call to convert a 1D matlab.double into a Python array.array object.