Python

jeg · 07-22-2002, 03:08 PM

Hello everyone, this is my first post here and isn't really linux-related, but I figure someone may be able to help anyway (and sooner or later I will most likely need help with linux too).

This is actually not a linux problem, it works fine on Linux but not on Windows.

I am trying to get it to work in Windows also because I'd like to use IDLE but haven't quite got xwindows working correctly yet.

I am writing a Yahtzee game in Python. It is not very good, but it is my first attempt at writing any sort of program longer than a few lines from scratch, so that's to be expected.

Code:

import random
...
class Die:
      def __init__(self, value=0):
            self.value = value

      def __str___(self):
            return str(self.value)

      def __cmp__(self.other):
            if self.value > other.value: return 1
            if self.value < other.value: return -1
            return 0

class DieSet:
      #'DieSet' is the five dice that are used each turn
      def __init__(self):
           self.set = []
           #gives each die a value from 1  to 6
           for die in range(5):
                 newDie = Die()
                  value = int(random.randrange(1, 7))
                  self.set.append(newDie(value))
...

Whenever I do anything with DieSet() (on Windows), it gives me this error:

AttributeError: Die instance has no __call__ method.

However, when I try to do the exact same thing on Linux, it all works fine. Does anyone know why it's giving me that error, or what to do about it? I don't know exactly what the __call__ method is, in the case it really is needed, and haven't found much helpful information on the Internet as of yet. I am using Python 2.2.1 on WindowsXP.

Maybe I should give up on Windows and do it all on Linux, huh?

Thanks in advance for any replies.
-jeg

DoubleLetter · 07-23-2002, 12:44 AM

Hi,

I think this is the error:

You are calling the Die class like this:
'newDie = Die()'

which is fine. Now you have an instance of the Die class in the variable newDie. Fine ?

newDie now holds an INSTANCE of the DIE class. An INSTANCE has methods; you have to access the functions/variables of an INSTANCE like this:
'newDie.value = 23'

or

'newDie.functionName(passedVariable)'

But you are using the INSTANCE itself as a class (!!!) by saying:

'newDie(value)'

It is absolutely incorrect.

from what I understand of your intentions, it should be:

'newDie.value = value'

Was I clear enough ?

Hope that helps !

Cheers,

Ahsan

jeg · 07-26-2002, 08:46 PM

Thank you! Yes, that did help.

I went back and tried again, both

Code:

value = int(random.randrange(1, 7))
newDie = Die(value)
self.set.append(newDie)

and

Code:

newDie = Die()
newDie.value = int(random.randrange(1, 7))
self.set.append(newDie)

work correctly. (maybe, originally, I tried to put part of each together (?) or something)

It seems obvious now that I know what the problem was, but I guess it never hurts to ask. And, now I'll be sure not to make that mistake again.

Thanks again.
-jeg