如何初始化列表对象的Numpy数组

Question

I'm trying to create a numpy array that looks like

array([[list([]), list([])],
       [list([]), list([])],
       [list([]), list([])]], dtype=object)

This array has shape (3,2) . However, whenever I do

np.array([[list(), list()], [list(), list()], [list(), list()]])

I end up getting

array([], shape=(3, 2, 0), dtype=float64)

How do I solve this?

Answer 1

You could use the following:

np.frompyfunc(list, 0, 1)(np.empty((3,2), dtype=object))  

We first turn list into a ufunc that takes no arguments and returns a single empty list, then apply it to an empty 3x2 array of object type.