数值数组numpy的对象数组 [英] Numpy object array of numerical arrays

问题描述

我想创建一个 DTYPE = np.object 一个数组，其中每个元素是一个数字式的，例如整数或浮点数的数组。例如：

I want to create an array with dtype=np.object, where each element is an array with a numerical type, e.g int or float. For example:

>>> a = np.array([1,2,3])
>>> b = np.empty(3,dtype=np.object)
>>> b[0] = a
>>> b[1] = a
>>> b[2] = a

创建我想要什么：

Creates what I want:

>>> print b.dtype
object

>>> print b.shape
(3,)

>>> print b[0].dtype
int64

但我想知道是否有不写3行6在同一行（尤其是因为我可能会想连接100阵列）的方法。我试过

but I am wondering whether there isn't a way to write lines 3 to 6 in one line (especially since I might want to concatenate 100 arrays). I tried

>>> b = np.array([a,a,a],dtype=np.object)

但其实这所有的元素转换为np.object：

but this actually converts all the elements to np.object:

>>> print b.dtype
object

>>> print b.shape
(3,)

>>> print b[0].dtype
object

没有人有任何想法如何避免这种情况？

Does anyone have any ideas how to avoid this?

推荐答案

这不完全pretty，但是......

It's not exactly pretty, but...

import numpy as np

a = np.array([1,2,3])
b = np.array([None, a, a, a])[1:]

print b.dtype, b[0].dtype, b[1].dtype
# object int32 int32

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