错误：必须使用“类名”实例作为第一个参数来调用未绑定方法“方法名”（取而代之的是classobj对象）

Question

I hope you guys can help me out here. I've been given this error from the following code:

Traceback (most recent call last):
  File "C:\Python27\Lib\idlelib\Tarea5.py", line 60, in <module>
    bg.addBandit(b)
TypeError: unbound method addBandit() must be called with BanditGroup instance as first argument (got classobj instance instead)

The code:

from numpy import *
from matplotlib import pyplot as p
class Bandit:
    power = random.uniform(15,46)
    life = random.uniform(40,81)
    def __init__(self, power, life):
        self.power = power
        self.life = life
class BanditGroup:
    def __init__(self,a):
        self.group = [a] #Where 'a' is an object of the class Bandit
    def addBandit(self,b):
        self.group.append(b) #Where 'b' is an object of the class Bandit
        return self.group

howmanygroups = random.randint(4,11)
i = 0
j = 0
while i <= howmanygroups:
    bg = BanditGroup
    howmanybandits = random.randint(1,11)
    while j <= howmanybandits:
        b = Bandit
        bg.addBandit(b) #<-- line 60
        j+=1
    bgposx = random.uniform(0,50000)
    bgposy = random.uniform(0,50000)
    p.plot(bgposx,bgposy,'r^')
    i+=1

I'd really appreciate if someone could tell me what's going on here. I started learning python 2.7 about 2 months ago. Thanks!

Answer 1

The problem is that addBandit requires an instance of BanditGroup to be used. Adding (...) after the class name will create one:

bg = BanditGroup(...)

Right now, you have bg pointing to the class itself , not an instance of it.

The same thing needs to be done here with Bandit :

b = Bandit(...)

---

Note: ... means to pass in the appropriate arguments. You made BanditGroup.__init__ with a required a parameter and Bandit.__init__ with required power and life parameters. Since I don't know what you want these to be, I left them out.

Answer 2

Try changing your code to (notice the parenthesis around class instantiation):

while i <= howmanygroups:
    bg = BanditGroup(a)
    howmanybandits = random.randint(1,11)
    while j <= howmanybandits:
        b = Bandit(power, life)
        bg.addBandit(b) #<-- line 60

Answer 3

Yes probably need parens when you create an instance of your Bandit and BanditGroup classes. Otherwise, you're assigning a class to your variables, not an instance of a class.

EG: bg = BanditGroup()