[Tutor] Methods that return instances of their own class?
David Perlman
dperlman at wisc.edu
Thu Oct 15 17:14:51 CEST 2009
I'm trying to figure out how to define a class so that its instances
have a method that return a different object of the same class.
In particular, I'm trying to run a simple prisoner's dilemma game, and
I want to make a "game" object that has a method which returns the
"game" object with the payoffs reversed; that is, the payoff matrix
from the other player's point of view. Basically a kind of transpose
which is specific to this application.
class Payoffs(list):
def __init__(self, value=None):
list.__init__(self)
if value==None: # use a default prisoner's dilemma
value=[[(3,3),(0,5)],
[(5,0),(1,1)]]
self.extend(value)
def __repr__(self):
l1="Your Choice: Cooperate Defect\n"
l2="My choice: -------------------------\n"
l3="Cooperate | (% 3d,% 3d) | (% 3d,% 3d) |\n" % (self[0]
[0][0], self[0][0][1], self[0][1][0], self[0][1][1])
l4=" ----------------------- \n"
l5="Defect | (% 3d,% 3d) | (% 3d,% 3d) |\n" % (self[1]
[0][0], self[1][0][1], self[1][1][0], self[1][1][1])
l6=" -------------------------\n"
return l1+l2+l3+l4+l5+l6
def transpose(self):
And that's where I'm at. How can I have the transpose method return
another Payoffs object? Here's the beginning of it:
def transpose(self):
trans=[[(self[0][0][1],self[0][0][0]), (self[1][0][1],self[1]
[0][0])],
[(self[0][1][1],self[0][1][0]), (self[1][1][1],self[1]
[1][0])]]
But now "trans" is type list, not type Payoffs. I don't know how to
get it into a Payoffs object so that the transpose will have my other
new methods.
Thanks very much. I searched for answers but I'm not sure what this
would be called, which made it hard to find.
--
-dave----------------------------------------------------------------
Unfortunately, as soon as they graduate, our people return
to a world driven by a tool that is the antithesis of thinking:
PowerPoint. Make no mistake, PowerPoint is not a neutral tool —
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of who makes decisions, what decisions they make and how
they make them. -Colonel T. X. Hammes, USMC
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