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Re: many constructors in a class?

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From Beth McNany <beth.mcnany@gmail.com>
Date Wed, 14 Aug 2013 10:40:03 -0400
Subject Re: many constructors in a class?
To climb65 <climb65@laposte.net>
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On Wed, Aug 14, 2013 at 10:16 AM, climb65 <climb65@laposte.net> wrote:

> Hello,
>
> here is a small basic question :
>
> Is it possible to have more than one constructor (__init__ function) in a
> class? For instance, to create an object with 2 different ways? If my
> memory is good, I think that with C++ it is possible.
>
> Thanks for your answer.
>
>
No, Python does not allow method overloading:

>>> class Test:
...  def __init__(self):
...    print "first init"
...  def __init__(self, arg):
...    print "init with arg"
...
>>> a = Test()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: __init__() takes exactly 2 arguments (1 given)

No error on actually writing the class, but only the last __init__ is
kept.  You could, however, emulate that behavior with optional arguments,
or something more sophisticated as the need may be.  This stackoverflow
question covers a few alternatives:
http://stackoverflow.com/questions/6434482/python-function-overloading

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Thread

many constructors in a class? climb65 <climb65@laposte.net> - 2013-08-14 14:16 +0000
  Re: many constructors in a class? Phil Le Bienheureux <phil.le.bienheureux@gmail.com> - 2013-08-14 16:46 +0200
  Re: many constructors in a class? duncan smith <buzzard@invalid.invalid> - 2013-08-14 16:07 +0100
  Re: many constructors in a class? Beth McNany <beth.mcnany@gmail.com> - 2013-08-14 10:40 -0400
  Re: many constructors in a class? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-08-14 18:40 -0400
  Re: many constructors in a class? Steven D'Aprano <steve@pearwood.info> - 2013-08-15 07:23 +0000
    Re: many constructors in a class? Fábio Santos <fabiosantosart@gmail.com> - 2013-08-15 11:09 +0100
    Re: many constructors in a class? Roy Smith <roy@panix.com> - 2013-08-15 09:00 -0400

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