A weird issue I have encountered today. Would appreciate an explanation for that behavior of np.array:
l1 = np.array([[1], [1]])
type(l1)
Out[43]: numpy.ndarray
l2 = np.array([[1, 2], [1]])
type(l2)
Out[44]: numpy.ndarray
But:
type(l1[0])
Out[45]: numpy.ndarray
type(l2[0])
Out[47]: list
Any ideas?
This behavior is due to the fact that both (or all, to be precise) elements are not in the same dimension.
Consider:
l1 = np.array([[1], [1, 2]])
print(type(l1[0]))
l2 = np.array([[1, 2], [1, 2]])
print(type(l2[0]))
Will output the (now) expected
<class 'list'>
<class 'numpy.ndarray'>
In order to get numpy.ndarray "all the way down" all elements (and nested elements) must have the same dimension.