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Re: Why does str not have a __radd__ method?

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On 08/13/2014 10:55 AM, Steven D'Aprano wrote:
> Ethan Furman wrote:
>
>> On 08/13/2014 09:00 AM, Steven D'Aprano wrote:
>>>
>>> What is the rationale for str not having __radd__ method?
>>
>> At a guess I would say because string only knows how to add itself to
>> other strings, so __add__ is sufficient.
>
> # Python 2.7
> py> "Hello" + u"World"
> u'HelloWorld'
> py> unicode.__radd__
> Traceback (most recent call last):
>    File "<stdin>", line 1, in <module>
> AttributeError: type object 'unicode' has no attribute '__radd__'

Well, unicode is a string type, right? ;)

And for the proof:

>>> 'hello'.__add__(u'world')
u'helloworld'
>>> u'hello'.__add__('world')
u'helloworld'


> My brain hurts.

An occupational hazard of unicode, surely.

--
~Ethan~

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Thread

Why does str not have a __radd__ method? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-14 02:00 +1000
  Re: Why does str not have a __radd__ method? Ethan Furman <ethan@stoneleaf.us> - 2014-08-13 10:27 -0700
    Re: Why does str not have a __radd__ method? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-14 03:55 +1000
      Re: Why does str not have a __radd__ method? Ethan Furman <ethan@stoneleaf.us> - 2014-08-13 11:22 -0700
      Re: Why does str not have a __radd__ method? Jason Swails <jason.swails@gmail.com> - 2014-08-13 14:36 -0400
        Re: Why does str not have a __radd__ method? wxjmfauth@gmail.com - 2014-08-13 23:24 -0700

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