Scott David Daniels wrote:
> Matthew Thorley wrote:
>
>> This may be a very rudimentary question, but here goes:
>
> From your questions, I believe you are not thinking of values as
> being distinct from the names and data structures that refer to them.
>
> What is the parent of 23 in the following expression?
>
> 1 + 11 * 2
>
> If you know that, what is the parent of 293 in the same expression?
>
>> If I have a simple dictionary, where the value is a class or function,
>> is there an interface through which it can discover what its key is?
>> Similar to index() for list.
>
>
> def keyfor(dictionary, element):
> for key, value in dictionary.iteritems():
> if value == element: # value is element if identity quest
> return key
> raise ValueError, element
>
>> On a similar note, if one object is part of another,
>
> This is the idea you have wrong. In C, C++, Java, and Fortran you
> might have objects part of other objects, but in Python objects refer
> to each other.
>
> How about this:
>
> class Holder(object): pass
>
> v = [1 + 11 * 2]
> w = [1, v, 3]
> d = {1: v}
> o = Holder()
> o.x = v
>
> What is the parent of v?
>
> Or even worse:
>
> v = [1]
> v[0] = v
>
> What is the parent of v now?
>
> --Scott David Daniels
> [EMAIL PROTECTED]
I see what your saying, but I my situation the values of the dictionary
are unique objects created by a parent object. Sorry :(, I didn't
explain that very well in my first post.
When the 'root object' is 'global' I see what your saying, but when
class A:
def __init__(self, container):
self.container=container
class B(dict):
def magice_get_parent(self):
...
class special_value():
def __init__(self, val):
self.val = val
def magic_get_key(self):
...
parent = A(B)
parent.container[x] = special_value(1)
parent.container[y] = special_value(2)
parent.container[z] = special_value(1)
In this example, in my mind, the following should happen, and in theory
using introspecition, actualy possible.
child = parent.container
D.magic_get_parent() #returns parent
value1 = parent.container[x]
value2 = parent.container[y]
value3 = parent.container[z]
value1.magic_get_key() #returns x
value2.magic_get_key() #returns y
value3.magic_get_key() #returns z
Let me know if I'm nutz!
--Matthew
--
http://mail.python.org/mailman/listinfo/python-list
