Saving List of Numpy 2D arrays using numpy.save (the arrays together are jagged)

After testing on my machine:

  import numpy as np
  np.save('testnp.npy', [[2,3,4],[1,2]])
  np.load('testnp.npy')
  #   array([[2, 3, 4], [1, 2]], dtype=object)

As shown in the example code, the loaded object is of type ndarray, but its data type is object. That means, np.save store an array of python objects, which can be anything. According to the documentation, it seems to use python pickle to pack those objects.

So you didn't find a backdoor, it behaves just as expected.

np.savez() would work in your situation. save each as a variable.