二维列表到 ndarray 的 np.ndarray

Question

I have a 2D list like this

import numpy as np
data=[[1,2],[2,3],[3,4]]

I want to turn this to np.ndarray.

I don't want to get this:

np.array(data).shape
#(3,2)

my expected is like this

result=np.array(np.array([1,2]),np.array([2,3]),np.array([3,4]))

result.dtype
result.shape
#np.ndarry
#(3,)
result[i].shape
result[i].dtype
#(2,)
#np.ndarry

what should i do this a lot

Answer 1

AS @hpaulj suggested in comments
You can create firstempty array of object type and then assign list to it like

data = [[1,2],[2,3],[3,4]]
result = np.empty(shape=len(data), dtype=object)

result[:] = [np.array(i) for i in data]
result
array([array([1, 2]), array([2, 3]), array([3, 4])], dtype=object)

result.shape
(3,)

Answer 2

You can try converting the list into an ndarray and then flattening it

np.array(data).flatten()

You can also specify order parameter in flatten to flatten in row-major ('C') or column-major ('F') order