Overriding the __new__ method

[Gerrit]

Christoph Groth wrote:
> According to my understanding, if float type's __init__ ignores its
> arguments then the value of `arg' above should be ignored.  Instead,
> the constructed object has the value 12.  Where is this 12 passed to
> the object being constructed?

To __new__.

>>> class Test(object):
...  def __new__(cls):
...   print "calling new"
...   return object.__new__(cls)
...  def __init__(self):
...   print "calling init"
...
>>> Test()
calling new
calling init
<__main__.Test object at 0xbf491f0c>

...they are both called, but it is constructed in __new__. __new__
returns the object, while __init__ returns nothing. __init__ is actually
called after initialization, because the initialization happens when
object.__new__ is called. Because it is an immutable type, it cannot be
changed after it has been initialized, so __init__ can't thange it.

Gerrit.

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