为什么python在这个类的第二个方法中抛出错误？

Question

为什么python在这个类的第二个方法中抛出错误？

class Lutany:
    formulaa = 0
    formulab = 0
    def __init__(self,num):
        self.num = num
        self.formulaa = self.formulaA()
        self.formulab = self.formulaB


    def formulaA(self):
        q = 0
        num = self.num
        while num > 0 :
            q += num + (num - 1)
            num = num - 1
        return q
        self.formulab = formulaB()

    def formulaB(self):
        num = self.num
        q = 0
        while num > 0 :
            q = q + (num * num)
            num = num - 1
        return (0.5 * q)


if(__name__ == '__main__'):

    l = Lutany(675)

    p = l.formulaa
    q = l.formulab 

    print " FormunlA returned " , str(p) , "  for 675 "
    print " FormulaB returned " , str(q) , "  for 675 " 

运行时出现以下错误：

~$ python lutany.py
Traceback (most recent call last):
File "lutany.py", line 30, in <module> 
l = Lutany(675) 
File "lutany.py", line 7, in init 
self.formulab = self.formulaB 
AttributeError: Lutany instance has no attribute 'formulaB'

Answer 1

您已经过多地缩进了formulaB()方法的块（尽管对该问题的编辑已经破坏了这一点的证据）。确保它位于类缩进正下方的缩进级别，而不是前一个方法的缩进级别。

Answer 2

当你说，在formalaA self.formulab = formulaB()你的意思是self.formulab = self.formulaB()？

Answer 3

您在这里遗漏了括号：self.formulab = self.formulaB。应该是self.formulab = self.formulaB()。