Finding the name of a class
Hello I'm looking for a Larry Bates that was in the Navy. Could this be you?? In CT in 1965??? In your 60's?? Please let me know I have been searching for over 10 yrs thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
John Salerno wrote: Shane Hathaway wrote: Don't forget to file a bug. I'm reluctant to call it a bug just yet. Here's more stuff below. There's obviously a difference between old- and new-style classes. It seems that as far as new-style is concerned, __name__ is an attribute of __class__ (along with a bunch of other stuff), but not of Foo itself. I'm not sure what you're saying. The class of a class is the 'type' builtin, unless metaclasses are involved. So your expression dir(Foo.__class__) is equivalent to dir(type), and the 'type' builtin happens to have a __name__ attribute that dir() notices. Take a look: class Foo(object): ... pass ... Foo.__class__ is type True Foo.__name__ 'Foo' Foo.__class__.__name__ 'type' The bug is that the expression dir(someclass), where the class is a user-defined class of either new or old style, never reveals to the user that the class object has a __name__ attribute. I tested this with Python versions 2.3 through 2.5b1. This is an education issue; since that important attribute is not in the list, newcomers are not likely to discover it, and may instead use strange incantations to get the name of a class. Do you want me to file the bug? Shane -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Shane Hathaway wrote: The bug is that the expression dir(someclass), where the class is a user-defined class of either new or old style, never reveals to the user that the class object has a __name__ attribute. I guess maybe it is a bug. This seems to be the relevant code to prove it: class Foo(object): pass dir(Foo) ['__class__', '__delattr__', '__dict__', '__doc__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__weakref__'] Foo.__name__ 'Foo' Tim can report it if he wants, since he found it first. Otherwise I'll do it and it will give me a chance to see how the bug reporting process works. -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Kirk Strauser wrote:
Bruno Desthuilliers wrote:
Kirk Strauser wrote:
class foo(object):
pass
how can I find its name, such as:
b = foo
I suppose you mean b = foo() ?
Actually, I meant 'b = foo' in this case - I want to find the name of the
class that b references,
Ok. Could have been a typo, just wanted to make sure.
The name of a class is in the attribute '__name__' of the class. The
class of an object is in the attribute '__class__' of the object.
I swear that didn't work earlier. Honest. :-)
Not sure if it works for old-style classes...
OK, now for the good stuff. In the code below, how can I find the name of
the class that 'bar' belongs to:
class Foo(object):
... def bar(self):
... pass
...
b = Foo.bar
dir(b)
['__call__', '__class__', '__cmp__', '__delattr__', '__doc__', '__get__',
'__getattribute__', '__hash__', '__init__', '__new__', '__reduce__',
'__reduce_ex__', '__repr__', '__setattr__', '__str__', 'im_class', 'im_func',
'im_self']
b.im_class
class '__main__.Foo'
b.im_class.__name__
'Foo'
b.__class__
This will give you the class of b itself. Remember that in Python,
everything and it's sister is an object - including functions, methods,
classes and modules.
In this case, b is a method object - IOW a descriptor that wraps a
function object.
--
bruno desthuilliers
python -c print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in '[EMAIL PROTECTED]'.split('@')])
--
http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Dennis Lee Bieber wrote:
On Tue, 01 Aug 2006 11:09:57 -0500, Kirk Strauser [EMAIL PROTECTED]
declaimed the following in comp.lang.python:
Actually, I meant 'b = foo' in this case - I want to find the name of the
class that b references, but the name of an instance (which may have zero
or many references to it).
Pardon... That gives the class object another name, neither of which
has any precedence over the other.
Not quite exactly. The 'b = foo' statement binds together name b and the
object foo - which in this case happens to be a class. OTOH, class
objects do have a __name__ attribute, which is not impacted by the binding.
b = Foo.bar
dir(b)
['__call__', '__class__', '__cmp__', '__delattr__', '__doc__', '__get__',
'__getattribute__', '__hash__', '__init__', '__new__', '__reduce__',
'__reduce_ex__', '__repr__', '__setattr__', '__str__', 'im_class',
'im_func', 'im_self']
b.__class__
type 'instancemethod'
b.__class__.__name__
'instancemethod'
I was sort of hoping that it would print 'Foo'.
But... you've just pulled the method out of the class
definition... Without supplying an instance, there is no linkage to a
class.
Yes there is. Method objects have an im_class attribute, that is a
reference to the class they were 'pulled out' from.
--
bruno desthuilliers
python -c print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in '[EMAIL PROTECTED]'.split('@')])
--
http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Larry Bates wrote:
Kirk Strauser wrote:
Given a class:
class foo(object):
pass
how can I find its name, such as:
b = foo
print something(b)
'foo'
I'm writing a trace() decorator for the sake of practice, and am trying to
print the name of the class that a traced method belongs to. This seems
like it should be easy, but I think I've been staring at the problem too
long.
print print b.__class__.__name__ gives what you want
Actually it should be b.__name__, since b refers to *class* foo.
b.__class__ is the metaclass (usually 'type' unless there's a custom
metaclass).
--
bruno desthuilliers
python -c print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in '[EMAIL PROTECTED]'.split('@')])
--
http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Kirk Strauser wrote: Larry Bates wrote: print print b.__class__.__name__ gives what you want That doesn't seem to do it, though. Here's the result of importing a module from my company's internally-developed library: from Daycos.TableCopier.copyfro import StateProcessor print StateProcessor.__class__.__name__ type I'm looking for something that would print 'StateProcessor' but am not having much luck. It looks like StateProcessor is a class; StateProcessor.__class__ is the class of a class, i.e. type. Try StateProcessor.__name__ Kent -- http://mail.python.org/mailman/listinfo/python-list
Finding the name of a class
Given a class: class foo(object): pass how can I find its name, such as: b = foo print something(b) 'foo' I'm writing a trace() decorator for the sake of practice, and am trying to print the name of the class that a traced method belongs to. This seems like it should be easy, but I think I've been staring at the problem too long. -- Kirk Strauser -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Kirk Strauser wrote:
Given a class:
class foo(object):
pass
how can I find its name, such as:
b = foo
I suppose you mean b = foo() ?
print something(b)
'foo'
The name of a class is in the attribute '__name__' of the class. The
class of an object is in the attribute '__class__' of the object.
class Foo(object):
... pass
...
b = Foo
b.__name__
'Foo'
b = Foo()
b.__class__.__name__
'Foo'
I'm writing a trace() decorator for the sake of practice, and am trying to
print the name of the class that a traced method belongs to. This seems
like it should be easy, but I think I've been staring at the problem too
long.
help(dir)
Help on built-in function dir in module __builtin__:
dir(...)
dir([object]) - list of strings
Return an alphabetized list of names comprising (some of) the attributes
of the given object, and of attributes reachable from it:
No argument: the names in the current scope.
Module object: the module attributes.
Type or class object: its attributes, and recursively the attributes of
its bases.
Otherwise: its attributes, its class's attributes, and recursively the
attributes of its class's base classes.
--
bruno desthuilliers
python -c print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in '[EMAIL PROTECTED]'.split('@')])
--
http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Kirk Strauser wrote: Given a class: class foo(object): pass how can I find its name, such as: b = foo print something(b) 'foo' I'm writing a trace() decorator for the sake of practice, and am trying to print the name of the class that a traced method belongs to. This seems like it should be easy, but I think I've been staring at the problem too long. print print b.__class__.__name__ gives what you want -Larry Bates -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
class Foo(object): ... pass ... b = Foo b.__name__ 'Foo' While this is surely true, would somebody explain why I had such trouble finding this? help(dir) Help on built-in function dir in module __builtin__: continuing from your example... dir(b) ['__class__', '__delattr__', '__dict__', '__doc__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__weakref__'] '__name__' in dir(b) False '__name__' *really is* a method of b as shown by your example lines, and can be successfully called. However, it *doesn't* show up when asked for via dir(b). Grumble. Is there a dir_and_i_really_mean_everything() function? I suppose problems (mostly with expectations) can ensue when you've got dynamic attributes, but this seems like something that dir() should be finding. -a puzzled tkc -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Tim Chase wrote: While this is surely true, would somebody explain why I had such trouble finding this? I think __name__ is an attribute of the class itself, not the instance: class Foo(object): pass f = Foo() f.__name__ Traceback (most recent call last): File pyshell#4, line 1, in -toplevel- f.__name__ AttributeError: 'Foo' object has no attribute '__name__' Foo.__name__ 'Foo' -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Larry Bates wrote: print print b.__class__.__name__ gives what you want That doesn't seem to do it, though. Here's the result of importing a module from my company's internally-developed library: from Daycos.TableCopier.copyfro import StateProcessor print StateProcessor.__class__.__name__ type I'm looking for something that would print 'StateProcessor' but am not having much luck. -- Kirk Strauser -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
John Salerno wrote: Tim Chase wrote: While this is surely true, would somebody explain why I had such trouble finding this? I think __name__ is an attribute of the class itself, not the instance: On the other hand: class Foo(object): pass dir(Foo) ['__class__', '__delattr__', '__dict__', '__doc__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__weakref__'] Hmmm. -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
While this is surely true, would somebody explain why I had such trouble finding this? I think __name__ is an attribute of the class itself, not the instance: That makes sense, but what doesn't make sense is why, when you do a dir(Foo), you don't get '__name__' in the returned list of available things Python knows about a Foo. class Foo(object): ... pass ... myClass = Foo myInstance = Foo() # does myClass have a '__name__' attribute? '__name__' in dir(myClass) False # that's a negative, buster '__name__' in dir(myInstance) False # haha, just kidding, it really did have a __name__ # proof that dir() isn't showing everything: myClass.__name__ 'Foo' myInstance.__name__ Traceback (most recent call last): File stdin, line 1, in ? AttributeError: 'Foo' object has no attribute '__name__' It's the '__name__' in dir(myClass) False myClass.__name__ 'Foo' that throws me. What other super-secret tricks have I missed because dir() didn't tell me about them? -a still-confused tkc -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
John Salerno wrote: class Foo(object): pass dir(Foo) ['__class__', '__delattr__', '__dict__', '__doc__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__weakref__'] Hmmm. Don't forget to file a bug. Shane -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Bruno Desthuilliers wrote: Kirk Strauser wrote: class foo(object): pass how can I find its name, such as: b = foo I suppose you mean b = foo() ? Actually, I meant 'b = foo' in this case - I want to find the name of the class that b references, but the name of an instance (which may have zero or many references to it). The name of a class is in the attribute '__name__' of the class. The class of an object is in the attribute '__class__' of the object. I swear that didn't work earlier. Honest. :-) OK, now for the good stuff. In the code below, how can I find the name of the class that 'bar' belongs to: class Foo(object): ... def bar(self): ... pass ... b = Foo.bar dir(b) ['__call__', '__class__', '__cmp__', '__delattr__', '__doc__', '__get__', '__getattribute__', '__hash__', '__init__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', 'im_class', 'im_func', 'im_self'] b.__class__ type 'instancemethod' b.__class__.__name__ 'instancemethod' I was sort of hoping that it would print 'Foo'. -- Kirk Strauser -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Shane Hathaway wrote: Don't forget to file a bug. I'm reluctant to call it a bug just yet. Here's more stuff below. There's obviously a difference between old- and new-style classes. It seems that as far as new-style is concerned, __name__ is an attribute of __class__ (along with a bunch of other stuff), but not of Foo itself. class Foo(object): pass dir(Foo) ['__class__', '__delattr__', '__dict__', '__doc__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__weakref__'] dir(Foo.__class__) ['__base__', '__bases__', '__basicsize__', '__call__', '__class__', '__cmp__', '__delattr__', '__dict__', '__dictoffset__', '__doc__', '__flags__', '__getattribute__', '__hash__', '__init__', '__itemsize__', '__module__', '__mro__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__subclasses__', '__weakrefoffset__', 'mro'] class Foo: pass dir(Foo) ['__doc__', '__module__'] dir(Foo.__class__) Traceback (most recent call last): File pyshell#9, line 1, in -toplevel- dir(Foo.__class__) AttributeError: class Foo has no attribute '__class__' -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Kirk Strauser wrote: [snip] OK, now for the good stuff. In the code below, how can I find the name of the class that 'bar' belongs to: class Foo(object): ... def bar(self): ... pass ... b = Foo.bar print b.im_class.__name__ Foo But if you are writing a decorator, you can use this code: import sys def tracer(func): A decorator that prints the name of the class from which it was called. The name is determined at class creation time. This works only in CPython, since it relies on the sys._getframe() function. The assumption is that it can only be called from a class statement. The name of the class is deduced from the code object name. classframe = sys._getframe(1) print classframe.f_code.co_name return func Hope this helps, Ziga -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Dennis Lee Bieber wrote: On Tue, 01 Aug 2006 10:56:52 -0500, Kirk Strauser [EMAIL PROTECTED] declaimed the following in comp.lang.python: Larry Bates wrote: print print b.__class__.__name__ gives what you want That doesn't seem to do it, though. Here's the result of importing a module from my company's internally-developed library: from Daycos.TableCopier.copyfro import StateProcessor print StateProcessor.__class__.__name__ type I'm looking for something that would print 'StateProcessor' but am not having much luck. And what is StateProcessor class SP(object): ... pass ... print SP.__class__.__name__ type Looks like it is, itself, the class, not something within the class. s=SP() print s.__class__.__name__ SP DP = SP d = DP() print DP.__class__.__name__ type print d.__class__.__name__ SP When I do this: class foo(object): pass if __name__==__main__: a=foo() print a.__class__.__name__ Note: You must do it on instance of the class not the class itself. it prints 'foo' for me. Not exactly sure why you get something very different. I've used this LOTS of times in my code, but I'll admit mostly with old-style classes. -Larry Bates -- http://mail.python.org/mailman/listinfo/python-list
Re: Finding the name of a class
Tim Chase a écrit : class Foo(object): ... pass ... b = Foo b.__name__ 'Foo' While this is surely true, would somebody explain why I had such trouble finding this? Mmm... Documentation needs update ? help(dir) Help on built-in function dir in module __builtin__: continuing from your example... dir(b) ['__class__', '__delattr__', '__dict__', '__doc__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__weakref__'] '__name__' in dir(b) False '__name__' *really is* a method s/method/attribute/ of b as shown by your example lines, and can be successfully called. However, it *doesn't* show up when asked for via dir(b). Grumble. Yes, as mentionned in the doc, dir() doesn't list *all* names in a namespace. DOn't ask me why nor how it chooses which ones it rejects, I wonder too. Is there a dir_and_i_really_mean_everything() function? Perhaps in the inspect module... -- http://mail.python.org/mailman/listinfo/python-list
