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Re: Is it correct this way to inherit from a list?

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On Sat, Mar 2, 2013 at 10:22 AM, Ian Kelly <ian.g.kelly@gmail.com> wrote:
> class Vector(list):
>     def __new__(cls, *args):
>         return super(Vector, cls).__new__(cls, args)
>     def __init__(self, *args):
>         super(Vector, self).__init__(args)
>
> The __new__ method here will receive the args in the style that you
> want, and then pass them up the inheritance chain to the superclass
> constructor, which will then just do the right thing.  The __init__
> method is also overridden to match the modified argspec.  The
> super().__init__() call is included for completeness; AFAIK it doesn't
> actually do anything.

I retract that.  On further testing, it is actually the __init__
method that initializes the list contents, not the __new__ method.  So
this is all you need:

class Vector(list):
    def __init__(self, *args):
        super(Vector, self).__init__(args)

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Thread

Is it correct this way to inherit from a list? gialloporpora <gialloporpora@gmail.com> - 2013-03-02 18:02 +0100
  Re: Is it correct this way to inherit from a list? Peter Otten <__peter__@web.de> - 2013-03-02 18:19 +0100
  Re: Is it correct this way to inherit from a list? Ian Kelly <ian.g.kelly@gmail.com> - 2013-03-02 10:22 -0700
  Re: Is it correct this way to inherit from a list? Ian Kelly <ian.g.kelly@gmail.com> - 2013-03-02 10:26 -0700
    Re: Is it correct this way to inherit from a list? gialloporpora <gialloporpora@gmail.com> - 2013-03-03 03:33 +0100
  Re: Is it correct this way to inherit from a list? Rick Johnson <rantingrickjohnson@gmail.com> - 2013-03-02 09:46 -0800
    Re: Is it correct this way to inherit from a list? gialloporpora <gialloporpora@gmail.com> - 2013-03-03 03:30 +0100
      Re: Is it correct this way to inherit from a list? Chris Angelico <rosuav@gmail.com> - 2013-03-03 14:18 +1100
      Re: Is it correct this way to inherit from a list? "Colin J. Williams" <cjw@ncf.ca> - 2013-03-03 09:21 -0500
        Re: Is it correct this way to inherit from a list? Jason Swails <jason.swails@gmail.com> - 2013-03-03 15:40 -0500

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