list_of_lists = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
an_array = np.array(list_of_lists)
# [[1, 2, 3], [4, 5, 6], [7, 8, 9]] [[1 2 3] [4 5 6] [7 8 9]]
non_rectangular = [[1, 2], [3, 4, 5], [6, 7, 8, 9]]
non_rectangular_array = np.array(non_rectangular)
# [[1, 2], [3, 4, 5], [6, 7, 8, 9]] [list([1, 2]) list([3, 4, 5]) list([6, 7, 8, 9])]
print(an_array.shape, an_array.dtype) # (3, 3) int64
print(non_rectangular_array.shape, non_rectangular_array.dtype) # (3,) object