How to find the classname of an object? (was Python Documentation)

[Heiko Wundram]

On Friday 13 May 2005 01:21, Christopher J. Bottaro wrote:
> For those of you following the Python Documentation thread, this is a good
> example of how the PHP manual is "better".  I found how to do this in a few
> seconds in PHP.  I searched the Python docs for "class name", "classname",
> "introspection" and "getclass".  I looked in the Class section of the
> tutorial also and also the Programming FAQ.  The "related functions"
> section of the PHP manual is really helpful.  It would be cool if in the
> section for the built-in function isinstance() or issubclass() there is a
> section for "related functions" that would point me to getclassname(obj)
> (if it exists).

There is no function to do this in Python (so you'll have a hard time finding 
it in the docs :-)), but there is a __bases__ member in any class/type which 
lists the immediate bases (and this is documented in the language reference, 
along with a reference in the tutorial when OO is introduced). Now, the 
following method lists all base classes:

def getBases(cls):
    bases = []
    stack = [cls]
    new_stack = []
    while stack:
        for cls in stack:
            if cls not in bases:
                bases.append(cls)
                new_stack.extend(cls.__bases__)
        stack = new_stack
        new_stack = []
    return bases

Example:

>>> class x(object):
...   pass
...
>>> class y(x):
...   pass
...
>>> class z(object):
...   pass
...
>>> class a(z,y):
...   pass
...
>>> def getBases(cls):
...     bases = []
...     stack = [cls]
...     new_stack = []
...     while stack:
...         for cls in stack:
...             if cls not in bases:
...                 bases.append(cls)
...                 new_stack.extend(cls.__bases__)
...         stack = new_stack
...         new_stack = []
...     return bases
...
>>> getBases(a)
[<class '__main__.a'>, <class '__main__.z'>, <class '__main__.y'>, <type 
'object'>, <class '__main__.x'>]

HTH!

--- Heiko.