Matt Williams wrote:
> Dear List,
>
> I'm stuck on trying to write a generic 'report' function:
>
> Class SomeClass:
> def __init__(self,a,b):
> self.a = a
> self.b = b
>
> def report(self):
> for i in dir(self):
> print self.i
>
> <Error Traceback......>
>
>
> This is where I run into problems: How do I return all of the variables
> in an instance?
If you are trying to show the data attributes of an instance then Karl's
suggestion of self.__dict__.items() is probably the best. dir() attempts to
show all accessible attributes, which may be instance variables, class methods,
class attributes, etc. For example:
>>> class F(object):
... def __init__(self):
... self.data = 1
... def show(self):
... print 'data =', self.data
...
>>> f=F()
>>> dir(f)
['__class__', '__delattr__', '__dict__', '__doc__', '__getattribute__',
'__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__'
, '__repr__', '__setattr__', '__str__', '__weakref__', 'data', 'show']
>>> f.__dict__
{'data': 1}
In this case f.__dict__ is probably what you want, not dir(f). However it's
easy to make an example where __dict__ doesn't contain all accessible
attributes, for example in a class that defines __slots__:
>>> class G(object):
... __slots__ = ['data']
... def __init__(self):
... self.data = 1
...
>>> g=G()
>>> g.__dict__
Traceback (most recent call last):
File "<stdin>", line 1, in ?
AttributeError: 'G' object has no attribute '__dict__'
>>> dir(g)
['__class__', '__delattr__', '__doc__', '__getattribute__', '__hash__',
'__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__'
, '__setattr__', '__slots__', '__str__', 'data']
>>> g.__slots__
['data']
>>>
A class that defines __getattr__ or __getattribute__ could have attributes that
don't appear in dir(), __dict__ or __slots__. So in general I think what you
want is hard. For common cases __dict__ will work.
Kent
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