Quesion about the proper use of __slots__

[Zefria]

>>> class Fighter:
... '''Small one man craft that can only harm other fighters on
their own.'''
... def __init__(self,statsTuple=(50,5,0,(2,4),1)):
... self.fuel = statsTuple[0]
... self.life = statsTuple[1]
... self.armor = statsTuple[2]
... self.weapon = statsTuple[3]
... self.bulk = statsTuple[4]
... __slots__ =
[self.fuel,self.life,self.armor,self.weapon,self.bulk]
...
>>> ral = Fighter()
>>> ral.rocks = 2
>>> ral.rocks
2
>>> ral.life
5

I was reading the special methods, got to slots
(http://docs.python.org/ref/slots.html) and decided that i should use
this to save memory in the program because it'll have to support very
large numbers of fighers at once. It says that once you define slots
then you can't add any variables not listed in slots, but from that
example section I just did, so am I doing something wrong or did I read
it wrong?

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Re: Quesion about the proper use of __slots__

[Zefria]

>>> class Fighter(object):
... '''Small one man craft that can only harm other fighters on
their own.'''
... __slots__ = ["fuel","life","armor","weapon","bulk"]
... def __init__(self,statsTuple=(50,5,0,(2,4),1)):
... self.fuel = statsTuple[0]
... self.life = statsTuple[1]
... self.armor = statsTuple[2]
... self.weapon = statsTuple[3]
... self.bulk = statsTuple[4]
...
>>> examp = Fighter()
>>> examp.rock = 3
Traceback (most recent call last):
  File "", line 1, in ?
AttributeError: 'Fighter' object has no attribute 'rock'
>>>

Thank you both, I had tried making it a class variable and didn't see
anything. The trick must have been in making a class that inheriets
from object.

Also, I don't generally do any optimization at all yet (as a highschool
student projects get trashed often enough no to bother over), but in
this special case I'm expecting each "carrier" to have up to 150
fighters, and 3 to 5 carriers for each of the two teams, which comes
out to be quite large.

Additionally, this program's purpose was to experiment with as many of
the special methods as possible, so I suppose I'm on track so far.

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Re: Quesion about the proper use of __slots__

[Zefria]

Well, my computer tends to run at about 497 to 501 out of 504 MB of RAM
used once I start up Gnome, XMMS, and a few Firefox tabs, and I'd
prefer not to see things slipping into Swap space if I can avoid it,
and the fighter data would be only part of a larger program.

And as I said, learning how to use __slots__ is important enough to
hazard a premature guess this time around. If I mess up, the worst that
happens is that I have to write down a new variable name in two places
instead of one now.

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Re: Quesion about the proper use of __slots__

[Zefria]

I am aware of this; but with too much Java still running through my
brain I've never bothered with the idea yet because that's simply not
the way I learned and I've never had a chance to need new attributes
for singular instances.

"__slots__ is not a method, so it falls outside that purpose as stated.
" -Alex Martelli

It's listed within the special methods section of the Python Refrence,
was what I ment.

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