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Re: What arguments are passed to the __new__ method ?

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On Wed, Mar 2, 2016 at 10:57 AM, Rob Gaddi
<rgaddi@highlandtechnology.invalid> wrote:
> Peter Pearson wrote:
>
>> On Tue, 1 Mar 2016 18:24:12 +0100, ast wrote:
>>>
>>> It's not clear to me what arguments are passed to the
>>> __new__ method. Here is a piece of code:
>>>
>>>
>>> class Premiere:
>>>
>>>     def __new__(cls, price):
>>>          return object.__new__(cls)
>>>
>>>     def __init__(self, price):
>>>             pass
>> [snip]
>>
>> Of course, maybe you don't need to define a __new__ method at all.
>> Personally, I find that __init__ suffices for my simple needs.
>>
>
> I tend to need __init__ on about half of the classes I write.  I think
> I've needed __new__ all of twice in the years I've been writing Python.

Typically there are only two reasons to override __new__: you
potentially want to return an object of a different class than the
class that was called, or you're subclassing an immutable type and
need to handle the superclass arguments before they get passed to the
constructor.

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Thread

What arguments are passed to the __new__ method ? "ast" <nomail@invalid.com> - 2016-03-01 18:24 +0100
  Re: What arguments are passed to the __new__ method ? eryk sun <eryksun@gmail.com> - 2016-03-01 13:54 -0600
  Re: What arguments are passed to the __new__ method ? Terry Reedy <tjreedy@udel.edu> - 2016-03-01 15:27 -0500
  Re: What arguments are passed to the __new__ method ? eryk sun <eryksun@gmail.com> - 2016-03-01 15:09 -0600
  Re: What arguments are passed to the __new__ method ? "ast" <nomail@invalid.com> - 2016-03-02 10:23 +0100
    Re: What arguments are passed to the __new__ method ? Steven D'Aprano <steve@pearwood.info> - 2016-03-02 22:02 +1100
  Re: What arguments are passed to the __new__ method ? Peter Pearson <pkpearson@nowhere.invalid> - 2016-03-02 17:40 +0000
    Re: What arguments are passed to the __new__ method ? Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2016-03-02 17:57 +0000
      Re: What arguments are passed to the __new__ method ? Ian Kelly <ian.g.kelly@gmail.com> - 2016-03-02 11:26 -0700

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