Question

I need to create a large matrix (array) structure (3 axis) and each element should store the reference to a Python object (myclass instance). Is it possible to use numpy to create such an array. Which data type should I use in order to store Python references?
The advantage of numpy is the support of slicing at different levels. The alternativee is to create a nested (nested) list but it is a cumbersome solution.

Answer 1

Use dtype=object to store Python objects in the array.

import numpy as np

class Foo: pass

arr=np.empty(2,dtype=object)
arr[:]=[Foo(),Foo()]
print(arr)
# [<__main__.Foo instance at 0xb7827d0c>
#  <__main__.Foo instance at 0xb748b5ac>]

print(arr.dtype)
# object