getattr(foo, 'foobar') not the same as foo.foobar?
- From: Dave Kuhlman <dkuhlman@xxxxxxxx>
- Date: Thu, 13 Mar 2008 22:06:05 GMT
The following code has me mystified:
In [4]: class A(object):
...: def show(self):
...: print 'hello'
...:
...:
In [5]: a = A()
In [6]:
In [7]: x = a.show
In [8]: y = getattr(a, 'show')
In [9]: x
Out[9]: <bound method A.show of <__main__.A object at 0xb557d0>>
In [10]: y
Out[10]: <bound method A.show of <__main__.A object at 0xb557d0>>
In [11]:
In [12]: id(x)
Out[12]: 12419552
In [13]: id(y)
Out[13]: 12419872
In [14]:
In [15]: x is y
Out[15]: False
In [16]:
In [17]: x()
hello
In [18]: y()
hello
Basically, the above code is saying that foo.foobar is not the same as
getattr(foo, 'foobar').
But the documentation at
http://docs.python.org/lib/built-in-funcs.html#l2h-33
says that they are equivalent.
And, the following seems even worse:
>>> id(getattr(a, 'show')) == id(a.show)
True
>>> getattr(a, 'show') is a.show
False
What gives? This breaks my understanding of id(), the is operator, and
getattr().
Can someone help me make sense of this?
I'm using Python 2.5.2.
- Dave
--
Dave Kuhlman
http://www.rexx.com/~dkuhlman
.
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