[Tutor] Unbound Method Error

[Prasad, Ramit]

Hi Greg,

You must use the class definition not an instance/object of it.  If the class is called CarClass
from some_lib_a.sub_lib_b import CarClass
[...]
isinstance(car, CarClass)
OR
import some_lib_a
[...]
isinstance(car, some_lib_a.sub_lib_b.CarClass)


The following does NOT work:
isinstance(car, CarClass())

if you want to check multiple classes use
isinstance(car, (Class1, Class2))

Ramit



Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology
712 Main Street | Houston, TX 77002
work phone: 713 - 216 - 5423

From: Greg Nielsen [mailto:gollumgreg407366 at gmail.com]
Sent: Monday, April 25, 2011 3:19 PM
To: Prasad, Ramit
Cc: Steven D'Aprano; tutor at python.org
Subject: Re: [Tutor] Unbound Method Error

Ramit,

     First, thank you for your input and insight into my problem, I believe that the code you came up with should not only be more efficient, but also clear up the last of my issues. I just have a quick question on the isinstance command you called. How exactly do I get the code to recognize it as a class I wrote sitting in an imported library file? I would guess that it would look sort of like this:

       if crash:
           for car in crash:
                if isinstance(car, redracersprites26.BlueCarSprite()):
                    redracersprites26.BlueCarSprite.collide(car, playerCar)

However, worded as it the follow error and call back happens:

Traceback (most recent call last):
  File "C:\Users\Greg\Documents\NetBeansProjects\Red Racer 26\src\redracer26.py", line 19, in <module>
    main()
  File "C:\Users\Greg\Documents\NetBeansProjects\Red Racer 26\src\redracer26.py", line 16, in main
    redracerstates26.game(startLives)
  File "C:\Users\Greg\Documents\NetBeansProjects\Red Racer 26\src\redracerstates26.py", line 87, in game
    if isinstance(car, redracersprites26.BlueCarSprite()):
TypeError: isinstance() arg 2 must be a class, type, or tuple of classes and types
I must be using the wrong syntax in the second argument. I think I should be able to find the documentation for this (extremely cool) method you showed me, but if you know the proper way to cite my object, could you send me what you think will work. This way I can have something to double check my work against if I don't get it right first time round. Thank you again for your time and assistance Ramit.

Greg


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