Python 2.6 numpy interaction array objects error

Question

I have a multi-dimensional array of objects. I want to interate over the objects using the nditer iterator. Here is a code example:

import numpy as np

class Test:
    def __init__(self,a):
        self.a = a
    def get_a(self):
        return self.a

b = np.empty((2,3),dtype = object)

t_00 = Test(0)
t_01 = Test(1)
t_11 = Test (11)

b[0,0] = t_00
b[0,1] = t_01
b[1,1] = t_11

for item in np.nditer(b,flags = ["refs_ok"]):
    if item:
        print item.get_a()

I would expect the "item" to contain the object reference that I can use to access data. However I am getting the following error:AttributeError: 'numpy.ndarray' object has no attribute 'get_a' My question is how can I go thru the array to access the object in the array?

Answer 1

The array.flat method of iteration will work, and can confirm that this works as you'd expect

for item in b.flat:
    if item:
        print item.get_a()

Answer 2

Iterating over an array with nditer gives you views of the original array's cells as 0-dimensional arrays. For non-object arrays, this is almost equivalent to producing scalars, since 0-dimensional arrays usually behave like scalars, but that doesn't work for object arrays.

If you were determined to go through nditer for this, you could extract the elements from the 0-dimensional views with the item() method:

for element in np.nditer(b,flags = ["refs_ok"]):
    element = element.item()
    if element:
        print(element.get_a())