Groups > comp.lang.python > #61979

Type of an object: ‘obj.class’ versus ‘type(obj)’

From	Ben Finney <ben+python@benfinney.id.au>
Subject	Type of an object: ‘obj.__class__’ versus ‘type(obj)’
Date	2013-12-16 12:51 +1100
Newsgroups	comp.lang.python
Message-ID	<mailman.4162.1387158693.18130.python-list@python.org> (permalink)

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Howdy all,

What is the Pythonic way to determine the type of an object? Are there
multiple valid ways, and when should each be used?

We have ‘obj.__class__’, an attribute bound to the object's class. Or is
it? When is that true, and when should we not rely on it?

We have ‘type(obj)’, calling the constructor for the ‘type’ type in
order to get a reference to the type of ‘obj’. Or is it? When is that
true, and when should we not rely on it?

Are there other ways to get at the type of a Python object? What reasons
are there to choose or avoid them?

-- 
 \         “Pinky, are you pondering what I'm pondering?” “I think so, |
  `\    Brain, but Zero Mostel times anything will still give you Zero |
_o__)                                  Mostel.” —_Pinky and The Brain_ |
Ben Finney

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Type of an object: ‘obj.__class__’ versus ‘type(obj)’ Ben Finney <ben+python@benfinney.id.au> - 2013-12-16 12:51 +1100
  Re: Type of an object: ‘obj.__class__’ versus ‘type(obj)’ Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-16 22:17 +0000
    Re: Type of an object: ‘obj.__class__’ versus ‘type(obj)’ dieter <dieter@handshake.de> - 2013-12-17 08:14 +0100
      Re: Type of an object: ‘obj.__class__’ versus ‘type(obj)’ Steven D'Aprano <steve@pearwood.info> - 2013-12-17 07:42 +0000
        Re: Type of an object: Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-17 23:35 +1300
          Re: Type of an object: Ethan Furman <ethan@stoneleaf.us> - 2013-12-17 06:50 -0800
          Re: Type of an object: Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-17 15:08 +0000
            Re: Type of an object: Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-18 11:15 +1300
              Re: Type of an object: Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-17 23:51 +0000
                Re: Type of an object: Ethan Furman <ethan@stoneleaf.us> - 2013-12-17 17:10 -0800
                Re: Type of an object: Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-19 00:45 +1300
                Re: Type of an object: Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-12-19 00:39 +1300

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