Replacing sub array in Numpy array

[ThemePark]

I'm trying to replace a sub array in a Numpy array, with an array of the same shape, such that any changes are mirrored in both arrays. I've run the following code in IDLE.

>>> import numpy
>>> a=numpy.zeros((2,1))
>>> a
array([[0.],
       [0.]])
>>> b=numpy.zeros((1))
>>> b
array([0.])
>>> a[0]=b
>>> b[0]=1
>>> b
array([1.])
>>> 

Now what I'd want the output of a to be in this example is:

array([[1.],
       [0.]])

but instead I get:

[b]array([[0.],
       [0.]])[/b]

I've been trying to read up on slicing and indexing, but it's not immediately obvious to me what I'm doing wrong here, or if it's even possible to get the result I want. So I was hoping someone could tell me how, if at all, I can do this.