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Groups > comp.lang.python > #16821

Re: I love the decorator in Python!!!

From K.-Michael Aye <kmichael.aye@gmail.com>
Subject Re: I love the decorator in Python!!!
Date 2011-12-08 12:22 +0100
Organization University of Bern
References <29996186.628.1323328726122.JavaMail.geo-discussion-forums@prfb7> <jbpu9j$1af$1@r03.glglgl.gl>
Newsgroups comp.lang.python
Message-ID <mailman.3405.1323343364.27778.python-list@python.org> (permalink)

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On 2011-12-08 08:59:26 +0000, Thomas Rachel said:

> Am 08.12.2011 08:18 schrieb 88888 Dihedral:
>> I use the @ decorator to behave exactly like a c macro that
>> does have fewer side effects.
>> 
>> I am wondering is there other interesting methods to do the
>> jobs in Python?
> 
> In combination with a generator, you can do many funny things.
> 
> 
> For example, you can build up a string:
> 
> def mkstring(f):
>      """Turns a string generator into a string,
>      joining with ", ".
>      """
>      return ", ".join(f())
> 
> def create_answer():
>      @mkstring
>      def people():
>          yield "Anna"
>          yield "John"
>          yield "Theo"
> 
>      return "The following people were here: " + people
> 
> 
> Many other things are thinkable...
> 
> 
> Thomas

I am still perplexed about decorators though, am happily using Python 
for many years without them, but maybe i am missing something?
For example in the above case, if I want the names attached to each 
other with a comma, why wouldn't I just create a function doing exactly 
this? Why would I first write a single name generator and then decorate 
it so that I never can get single names anymore (this is the case, 
isn't it? Once decorated, I can not get the original behaviour of the 
function anymore.
So, above, why not
def mkstring(mylist):
with the same function declaration and then just call it with a list of 
names that I generate elsewhere in my program?
I just can't identify the use-case for decorators, but as I said, maybe 
I am missing something.

Michael

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Thread

I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-07 23:18 -0800
  Re: I love the decorator in Python!!! Chris Rebert <clp2@rebertia.com> - 2011-12-08 00:04 -0800
  Re: I love the decorator in Python!!! Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-12-08 09:59 +0100
    Re: I love the decorator in Python!!! Chris Angelico <rosuav@gmail.com> - 2011-12-08 20:37 +1100
    Re: I love the decorator in Python!!! K.-Michael Aye <kmichael.aye@gmail.com> - 2011-12-08 12:22 +0100
      Re: I love the decorator in Python!!! Francesco Bochicchio <bieffe62@gmail.com> - 2011-12-09 04:00 -0800
    Re: I love the decorator in Python!!! Chris Angelico <rosuav@gmail.com> - 2011-12-08 22:43 +1100
      Re: I love the decorator in Python!!! Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-12-09 10:57 +0100
      Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-09 10:28 -0800
        Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-09 16:21 -0800
        Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-09 16:21 -0800
          Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-10 06:04 -0800
            Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-10 06:09 -0800
              Re: I love the decorator in Python!!! alex23 <wuwei23@gmail.com> - 2011-12-11 19:35 -0800
            Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-10 06:09 -0800
          Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-10 06:04 -0800
      Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-09 10:28 -0800
    Re: I love the decorator in Python!!! K.-Michael Aye <kmichael.aye@gmail.com> - 2011-12-08 17:24 +0100
    Re: I love the decorator in Python!!! Chris Angelico <rosuav@gmail.com> - 2011-12-09 03:38 +1100
      Re: I love the decorator in Python!!! alex23 <wuwei23@gmail.com> - 2011-12-08 21:02 -0800
        Re: I love the decorator in Python!!! Robert Kern <robert.kern@gmail.com> - 2011-12-09 10:08 +0000
          Re: I love the decorator in Python!!! alex23 <wuwei23@gmail.com> - 2011-12-11 19:36 -0800
            Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-11 20:51 -0800
              Re: I love the decorator in Python!!! alex23 <wuwei23@gmail.com> - 2011-12-11 21:47 -0800
                Re: I love the decorator in Python!!! 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-12 04:16 -0800
            Re: I love the decorator in Python!!! Ethan Furman <ethan@stoneleaf.us> - 2011-12-11 23:47 -0800
            Re: I love the decorator in Python!!! Robert Kern <robert.kern@gmail.com> - 2011-12-12 16:27 +0000
              Re: I love the decorator in Python!!! alex23 <wuwei23@gmail.com> - 2011-12-12 16:46 -0800
    Re: I love the decorator in Python!!! Andrew Berg <bahamutzero8825@gmail.com> - 2011-12-08 10:54 -0600
    Re: I love the decorator in Python!!! Andrew Berg <bahamutzero8825@gmail.com> - 2011-12-08 10:55 -0600
    Re: I love the decorator in Python!!! Ethan Furman <ethan@stoneleaf.us> - 2011-12-08 15:34 -0800
    Re: I love the decorator in Python!!! Ethan Furman <ethan@stoneleaf.us> - 2011-12-08 15:56 -0800

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