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From: Paul Kölle on 30 Apr 2010 10:17
Am 30.04.2010 13:05, schrieb Stefan Krastanov:
> Hello all,

[snipp]

> Here is the problem:
> I have a class (call it Data) that has a number of NumPy arrays and some
> methods that get useful information from the arrays (math stuff).
> I have two other classes (called Viewer1 and Viewer2) (they are subclasses
> of QAbstractTableModel but that's not important).
> I am working in my code with one instance of each class. Viewer1 and Viewer2
> must be able to call methods from the Data instance, but as the instance of
> Data is constantly updated, I cannot just copy it.
Why do you think the data is copied? Both viewers will hold a reference
to the same data object:

Type "help", "copyright", "credits" or "license" for more information.
>>> class d(object):
.... a = 1
.... b = 2
.... c = 3
....
>>> d1 = d()
>>> d1.a
1
>>> class view1(object):
.... def __init__(self, data):
.... self.data = data
.... def data(self):
.... return self.data
....
>>> class view2(object):
.... def __init__(self, data):
.... self.data = data
.... def data(self):
.... return self.data
....
>>> v1 = view1(d1)
>>> v2 = view2(d1)
>>> v2.data.b
2
>>> v2.data.b = 4
>>> v2.data.b
4
>>> v1.data.b
4
>>>

hth
Paul




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