Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #75587

Re: Correct type for a simple "bag of attributes" namespace object

Show key headers only | View raw

----- Original Message -----

> From: Peter Otten <__peter__@web.de>
> To: python-list@python.org
> Cc: 
> Sent: Sunday, August 3, 2014 11:37 AM
> Subject: Re: Correct type for a simple "bag of attributes" namespace object
> 
> Albert-Jan Roskam wrote:
> 
>>  I find the following obscure (to me at least) use of type() useful exactly
>>  for this "bag of attributes" use case:
>>>>>  employee = type("Employee", (object,), {})
>>>>>  employee.name = "John Doe"
>>>>>  employee.position = "Python programmer"
>>>>>  employee.name, employee.position, employee
>>  ('John Doe', 'Python programmer', <class 
> '__main__.Employee'>)
> 
> Are you sure you know what you are doing? The above is equivalent to
> 
>>>>  class employee:
> ...     name = "John Doe"
> ...     position = "Python programmer"
> ... 
>>>>  employee.name, employee.position, employee
> ('John Doe', 'Python programmer', <class 
> '__main__.employee'>)
>>>>  type(employee)
> <class 'type'>
> 
> Basically you are using classes as instances. While there is no fundamental 
> difference between classes and instances in Python you'll surprise readers 
> of your code and waste some space:

Yes, I know that it is equivalent, but I have always found it kind of ugly to use class() just to bundle a number of items. Like you are 'announcing OOP' (not sure how to put this into words), and then it's merely a simple bundle. Or maybe it's just me being silly, because it's even in the Python tutorial: https://docs.python.org/2/tutorial/classes.html#odds-and-ends
 
>>>>  import sys
>>>>  sys.getsizeof(employee)
> 976
>>>>  class Employee: pass
> ... 
>>>>  employee = Employee()
>>>>  employee.name = "John Doe"
>>>>  employee.position = "Python programmer"
>>>>  sys.getsizeof(employee)
> 64
Wow, I was not aware of that at all. So they are not equivalent after all. 

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

3 Suggestions to Make Python Easier For Children Mark Summerfield <list@qtrac.plus.com> - 2014-08-01 23:45 -0700
  Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-02 10:14 +0300
    Re: 3 Suggestions to Make Python Easier For Children Mark Summerfield <list@qtrac.plus.com> - 2014-08-02 00:38 -0700
      Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-02 11:03 +0300
        Re: 3 Suggestions to Make Python Easier For Children Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-03 02:00 +1000
          Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-02 20:07 +0300
            Re: 3 Suggestions to Make Python Easier For Children Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-02 18:29 +0100
              Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-02 21:33 +0300
    Re: 3 Suggestions to Make Python Easier For Children Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-03 01:43 +1000
      Correct type for a simple “bag of attributes” namespace object (was: 3 Suggestions to Make Python Easier For Children) Ben Finney <ben+python@benfinney.id.au> - 2014-08-03 05:58 +1000
        Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Mark Summerfield <list@qtrac.plus.com> - 2014-08-02 13:46 -0700
          Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Chris Angelico <rosuav@gmail.com> - 2014-08-03 07:05 +1000
          Re: Correct type for a simple "bag of attributes" namespace object Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-02 22:16 +0100
          Re: Correct type for a simple "bag of attributes" namespace object Chris Angelico <rosuav@gmail.com> - 2014-08-03 07:24 +1000
          Re: Correct type for a simple "bag of attributes" namespace object Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-02 22:23 +0100
          Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-08-02 16:18 -0700
          Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Chris Angelico <rosuav@gmail.com> - 2014-08-03 09:27 +1000
          Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Ian Kelly <ian.g.kelly@gmail.com> - 2014-08-02 18:59 -0600
          Re: Correct type for a simple "bag of attributes" namespace object Terry Reedy <tjreedy@udel.edu> - 2014-08-02 22:40 -0400
          Re: Correct type for a simple "bag of attributes" namespace object Terry Reedy <tjreedy@udel.edu> - 2014-08-02 22:43 -0400
          Re: Correct type for a simple "bag of attributes" namespace object Albert-Jan Roskam <fomcl@yahoo.com> - 2014-08-03 02:17 -0700
          Re: Correct type for a simple "bag of attributes" namespace object Peter Otten <__peter__@web.de> - 2014-08-03 11:37 +0200
          Re: Correct type for a simple "bag of attributes" namespace object Albert-Jan Roskam <fomcl@yahoo.com> - 2014-08-03 03:51 -0700
          Re: Correct type for a simple "bag of attributes" namespace object Albert-Jan Roskam <fomcl@yahoo.com> - 2014-08-03 04:14 -0700
          Re: Correct type for a simple "bag of attributes" namespace object Peter Otten <__peter__@web.de> - 2014-08-03 13:23 +0200
            Re: Correct type for a simple "bag of attributes" namespace object Marko Rauhamaa <marko@pacujo.net> - 2014-08-03 17:51 +0300
              Re: Correct type for a simple "bag of attributes" namespace object Roy Smith <roy@panix.com> - 2014-08-03 11:09 -0400
                Re: Correct type for a simple "bag of attributes" namespace object Marko Rauhamaa <marko@pacujo.net> - 2014-08-03 18:52 +0300
              Re: Correct type for a simple "bag of attributes" namespace object Terry Reedy <tjreedy@udel.edu> - 2014-08-03 18:55 -0400
                Re: Correct type for a simple "bag of attributes" namespace object Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-04 11:19 +1000
                Re: Correct type for a simple "bag of attributes" namespace object Terry Reedy <tjreedy@udel.edu> - 2014-08-04 01:26 -0400
              Re: Correct type for a simple "bag of attributes" namespace object Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-04 10:13 +1000
                Re: Correct type for a simple "bag of attributes" namespace object Roy Smith <roy@panix.com> - 2014-08-03 20:59 -0400
                Re: Correct type for a simple "bag of attributes" namespace object Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-08-04 13:00 +1200
                Re: Correct type for a simple "bag of attributes" namespace object Marko Rauhamaa <marko@pacujo.net> - 2014-08-04 08:41 +0300
                Re: Correct type for a simple "bag of attributes" namespace object Ian Kelly <ian.g.kelly@gmail.com> - 2014-08-04 00:41 -0600
                Re: Correct type for a simple "bag of attributes" namespace object Marko Rauhamaa <marko@pacujo.net> - 2014-08-04 09:57 +0300
          Re: Correct type for a simple "bag of attributes" namespace object Akira Li <4kir4.1i@gmail.com> - 2014-08-03 18:22 +0400
      Re: Correct type for a simple “bag of attributes” namespace object Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-03 13:28 +0100
        Re: Correct type for a simple “bag of attributes” namespace object Roy Smith <roy@panix.com> - 2014-08-03 08:40 -0400
          Re: Correct type for a simple “bag of attributes” namespace object Chris Angelico <rosuav@gmail.com> - 2014-08-03 22:56 +1000
            Re: Correct type for a simple “bag of attributes” namespace object Roy Smith <roy@panix.com> - 2014-08-03 09:25 -0400
              Re: Correct type for a simple “bag of attributes” namespace object Chris Angelico <rosuav@gmail.com> - 2014-08-03 23:35 +1000
                Re: Correct type for a simple “bag of attributes” namespace object Roy Smith <roy@panix.com> - 2014-08-03 10:36 -0400
                Re: Correct type for a simple “bag of attributes” namespace object Chris Angelico <rosuav@gmail.com> - 2014-08-04 01:00 +1000
      Re: Correct type for a simple “bag of attributes” namespace object Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-03 18:38 +0100
        Re: Correct type for a simple “bag of attributes” namespace object Roy Smith <roy@panix.com> - 2014-08-03 13:44 -0400
  Re: 3 Suggestions to Make Python Easier For Children Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-02 08:46 +0100
    Re: 3 Suggestions to Make Python Easier For Children Mark Summerfield <list@qtrac.plus.com> - 2014-08-02 01:03 -0700
      Re: 3 Suggestions to Make Python Easier For Children Terry Reedy <tjreedy@udel.edu> - 2014-08-02 19:14 -0400
  Re: 3 Suggestions to Make Python Easier For Children Terry Reedy <tjreedy@udel.edu> - 2014-08-02 19:12 -0400
  Re: 3 Suggestions to Make Python Easier For Children Brian Blais <bblais@gmail.com> - 2014-08-05 07:36 -0400
    Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-05 15:04 +0300
      Re: 3 Suggestions to Make Python Easier For Children Skip Montanaro <skip@pobox.com> - 2014-08-05 07:31 -0500
        Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-05 16:19 +0300
          Re: 3 Suggestions to Make Python Easier For Children MRAB <python@mrabarnett.plus.com> - 2014-08-05 15:11 +0100
          Re: 3 Suggestions to Make Python Easier For Children Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-06 02:14 +1000
      Re: 3 Suggestions to Make Python Easier For Children Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-05 22:43 +1000
        Re: 3 Suggestions to Make Python Easier For Children Chris Angelico <rosuav@gmail.com> - 2014-08-05 23:08 +1000
      Re: 3 Suggestions to Make Python Easier For Children Chris Angelico <rosuav@gmail.com> - 2014-08-05 23:00 +1000

csiph-web