Alex Hall wrote:
> On 5/21/10, Christian Heimes <li...@cheimes.de> wrote:
>> Am 21.05.2010 04:56, schrieb Alex Hall:
>>> Hi all,
>>> I am now trying to allow my classes, all of which subclass a single
>>> class (if that is the term), to provide optional arguments. Here is
>>> some of my code:
>>>
>>> class Craft():
>>> def __init__(self,
>>> name,
>>> isAircraft=False,
>>> id=helpers.id(),
>>> hits=0,
>>> weapons=[]):
>>
>> I hope you are aware that helpers.id() is called just once when the
>> *class* is defined and that the list weapons is shared across all
>> instances of the craft class. :)
> I know id is called once, but what do you mean weapons is shared?
All Craft instances for which you don't provide a weapons argument
explicitly will share the same list. If you later append a weapon to that
list all these Craft instances will see this change and get the extra
weapon:
a = Craft("first")
b = Craft("second")
a.weapons.append("surprise")
print b.weapons # ['surprise']
Peter
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