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Re: operator module functions

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On Wed, Oct 8, 2014 at 7:46 PM,  <marco.nawijn@colosso.nl> wrote:
> For me it makes sense. operator.add should be used in a "global" context
> (I don't know how to express it otherwise). So you provide it with the
> two values that you want to add. The .__add__ variants are bound to a
> particular instance and you provide it with a single value that you want
> to add.

What Steven's talking about is this:

>>> operator.add is operator.__add__
True

It's the exact same function, just accessed with a different name.

> As an example, you cannot use the dunder versions for literals.
>
>>> 2.__add__(3) # Oops, does not work
>>> a = 2
>>> a.__add__(3)
> 5

That's actually just a syntactic issue with integers and the dot. It
works fine if you use any other form of literal, or if you put a space
between the digits and the dot, or use parentheses, or anything; this
is the case with all methods off integers, not just dunder ones.

>>> 2 .__add__(3)
5
>>> (2).__add__(3)
5
>>> 2.0.__add__(3.0)
5.0

The object is exactly the same whether you reference the literal '2'
or the name 'a' that you've bound to it, so its methods must by
definition all be there.

ChrisA

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Thread

operator module functions Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-08 12:41 +1100
  Re: operator module functions Terry Reedy <tjreedy@udel.edu> - 2014-10-08 02:28 -0400
  Re: operator module functions marco.nawijn@colosso.nl - 2014-10-08 01:46 -0700
    Re: operator module functions Chris Angelico <rosuav@gmail.com> - 2014-10-08 20:32 +1100
      Re: operator module functions Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-10-09 10:37 +1300
        Re: operator module functions Chris Angelico <rosuav@gmail.com> - 2014-10-09 09:30 +1100
        Re: operator module functions Chris Kaynor <ckaynor@zindagigames.com> - 2014-10-08 15:40 -0700
    Re: operator module functions Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-08 21:57 +1100
      Re: operator module functions Terry Reedy <tjreedy@udel.edu> - 2014-10-08 15:09 -0400
      Re: operator module functions Ethan Furman <ethan@stoneleaf.us> - 2014-10-08 12:38 -0700
      Re: operator module functions random832@fastmail.us - 2014-10-08 15:49 -0400
      Re: operator module functions Gelonida N <gelonida@gmail.com> - 2014-10-08 23:05 +0200
      Re: operator module functions Ian Kelly <ian.g.kelly@gmail.com> - 2014-10-08 15:23 -0600
      Re: operator module functions Ethan Furman <ethan@stoneleaf.us> - 2014-10-08 14:49 -0700
      Re: operator module functions Chris Kaynor <ckaynor@zindagigames.com> - 2014-10-08 14:21 -0700
      Re: operator module functions Ben Finney <ben+python@benfinney.id.au> - 2014-10-09 08:57 +1100
      Re: operator module functions Terry Reedy <tjreedy@udel.edu> - 2014-10-08 18:46 -0400
      Re: operator module functions Ethan Furman <ethan@stoneleaf.us> - 2014-10-08 16:35 -0700
      Re: operator module functions Ned Batchelder <ned@nedbatchelder.com> - 2014-10-08 21:41 -0400

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