Mark Russo wrote:
In IronPython 2.0, when I replace a Point object in a list using
assignment, a copy of the Point object is used to replace the original
list element rather than the original Point itself. This does not
happen with user-defined objects. It also does not happen with Point
objects in IronPython 1.1.
Point objects are value types, so some operations cause them to be
copied. Probably the way they are used under the hood has changed with
IronPython 2.
Michael
IronPython 2.0 (2.0.0.0) on .NET 2.0.50727.3053
Type "help", "copyright", "credits" or "license" for more information.
>>> import clr
>>> clr.AddReference("System.Drawing")
>>> from System.Drawing import *
>>>
>>> class C(object): pass
...
>>> def test1():
... p1 = C() # Create two objects
... p2 = C()
... l = [p1] # Put one in a list
... print id(l[-1]), id(p2) # Print ids of object in list (p1) and p2
... l[-1] = p2 # Replace p1 with p2 in list
... print id(l[-1]), id(p2) # Print ids of object in list and p2
...
>>> def test2():
... p1 = Point(1,2) # Create two Points
... p2 = Point(3,4)
... l = [p1] # Put one in a list
... print id(l[-1]), id(p2) # Print ids of Point in list (p1) and p2
... l[-1] = p2 # Replace p1 with p2 in list
... print id(l[-1]), id(p2) # Print ids of Point in list and p2
...
>>> test1()
43 44
44 44
>>> test2()
45 46
47 46 # The id of the Point before and after adding to the list is
different
>>>
Here is the same program in IronPython 1.1
IronPython 1.1 (1.1) on .NET 2.0.50727.3053
Copyright (c) Microsoft Corporation. All rights reserved.
<snip>
>>> test1()
43 44
44 44
>>> test2()
45 46
46 46 # The id of the Point before and after adding to the list is
the same
>>>
... or am I missing something.
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