Numpy problem: Arrays in a list of dictionaries

[ZMY]

I am new to Numpy/Pylab, and I am trying to construct a list of
dictionaries with arrays as the items, for example:

>>> dict = {1: array([2, 3, 4]), 2: ''}
>>> list1 = []
>>> for i in range(3): list1.append(dict.copy())
...
>>> list1
[{1: array([2, 3, 4]), 2: ''}, {1: array([2, 3, 4]), 2: ''}, {1:
array([2, 3, 4]), 2: ''}]
>>> list1[0][1][1]=100
>>> list1
[{1: array([  2, 100,   4]), 2: ''}, {1: array([  2, 100,   4]), 2:
''}, {1: array([  2, 100,   4]), 2: ''}]

>>> list1[0][2]='Jack'
>>> list1
[{1: array([  2, 100,   4]), 2: 'Jack'}, {1: array([  2, 100,   4]),
2: ''}, {1: array([  2, 100,   4]), 2: ''}]

So the strings can be assigned seperately but arrays can not. What is
the problem here?

I am using python2.4+Numpy1.0.1 on Fedora

Thanks a lot in advance.

- ZMY