weights and neighbor attributes of W are not read-only

[GoogleCodeExporter]

>>> w=lat2W(2,2)
>>> w.neighbors
{0: [2, 1], 1: [0, 3], 2: [0, 3], 3: [1, 2]}
>>> w.cardinalities
{0: 2, 1: 2, 2: 2, 3: 2}
>>> w.neighbors[0]=[1]
>>> w.cardinalities
{0: 2, 1: 2, 2: 2, 3: 2}
>>> 

we could make them both private attributes/properties but this only protects 
neighbors from 
being defined as another dict (or list, or string), it doesn't protect 
individual elements of 
neighbors (or weights). in other words if you have a private attribute say 
something like:

>>> class W(object):
    def __init__(self,weights):
        self.__weights=weights
    @property
    def weights(self):
        return self.__weights

>>> w=W({0:[1],1:[0,2],2:[1]})
>>> w.weights
{0: [1], 1: [0, 2], 2: [1]}
>>> w.weights={0:[1,4],1:[0,2],2:[1],4:[0]}
------------------------------------------------------------
Traceback (most recent call last):
  File "<ipython console>", line 1, in <module>
AttributeError: can't set attribute

# note that is what we want since we don't want w.weights to change. but:

>>> w.weights
{0: [1], 1: [0, 2], 2: [1]}
>>> w.weights[0]='not protected'
>>> w.weights
{0: 'not protected', 1: [0, 2], 2: [1]}
>>> 

# which is definitely not what we want

Original issue reported on code.google.com by sjsrey on 28 May 2010 at 2:22

[GoogleCodeExporter]

Here is a Read_Only_dict, that might help...

Original comment by schmi...@gmail.com on 29 May 2010 at 12:32

Attachments:

• readonly_dict.py

[GoogleCodeExporter]

Original comment by sjsrey on 29 May 2010 at 6:26

• Changed state: Fixed