In version 0.9.6 one used to be able to do this:

In [4]: numpy.__version__
Out[4]: '0.9.6'

In [6]: numpy.array([numpy.array([4,5,6]), numpy.array([1,2,3])],
dtype=object).shape
Out[6]: (2, 3)

In beta 1 numpy.PyObject no longer exists. I was trying to get the
same behavior with dtype=object but it doesn't work:

In [7]: numpy.__version__
Out[7]: '1.0b1'

In [8]: numpy.array([numpy.array ([4,5,6]), numpy.array([1,2,3])],
dtype=object).shape
Out[8]: (2,)

The latter looks more correct, in that is produces an array of objects. To get the previous behaviour there is the function vstack:

In [6]: a = array([1,2,3])

In [7]: b = array([4,5,6])

In [8]: vstack([a,b])
Out[8]:
array([[1, 2, 3],
[4, 5, 6]])

Chuck