将列表传递给 __init__() 方法时超出最大递归深度错误

Question

我正在尝试创建一个基本的数学编程环境，类似于 sage，但非常基本。我已经定义了类functionClass，以及一个从其基类继承属性functionClass.x 的子类poly。

基类poly 的__init__() 方法除了使用functionClass 的x 之外，还接受一个名为coeffs 的列表（对应于多项式的系数）。

出于某种奇怪的原因，我在对象第一次实例化时收到了 RecursionError: maximum recursion depth exceeded 消息。我有点困惑，因为这一切都发生在poly 的__init__() 方法中......快速指针会很有帮助！

这是我目前所得到的：

import math
import operator

class functionClass:

    functions = {0: math.sin, 1: math.cos, 2: math.tan, 3: math.exp, 4: 'identity'}


    def __init__(self,option_code=0,x=0):
        self._option_code = option_code
        self._x = x
    @property
    def code(self):
        return self._option_code
    @code.setter
    def code(self,new_code):
        self._option_code = new_code

    @property
    def x(self):
        return self._x
    @x.setter
    def x(self,new_x):
        self._x = new_x

    def f_x(self):
        if self.code in self.functions:
            return self.functions[self.code](self.x)

    def __add__(self,other):
        sum = self.f_x() + other.f_x()
        return sum

    def __sub__(self,other):
        difference = self.f_x() - other.f_x()
        return difference

    def __mul__(self,other): 
        product = self.f_x() * other.f_x()
        return product

    def __truediv__(self,other):
        quotient = self.f_x() / other.f_x()
        return quotient


#class poly(functionClass)-------------------------------------------------------------------------------------------------------
class poly(functionClass):
    def __init__(self,coeffs,x):
        self.coeffs = coeffs
        print(self.coeffs)
        self.degree = len(coeffs)
        functionClass.x = x


    @property
    def coeffs(self):
        return self.coeffs

    @coeffs.setter
    def coeffs(self,new_coeffs):#TAKES IN A LIST
        self.coeffs= new_coeffs


    #test this
    def p_x(self):
        sum = 0
        for i in range(self.degree):
            sum = sum + (self.coeffs[i] * math.pow(x,i))
        return sum

    def __add__(self,other):
        pass

    def __sub__(self,other):
        pass

    def __mul__(self,other):
        pass

当我运行i=poly([1,1,1],1) 时，我得到了这个：

Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    i = poly([1,1,1],1)
  File "C:\Python\numInt.py", line 76, in __init__
    self.coeffs = coeffs
  File "C:\Python\numInt.py", line 88, in coeffs
    self.coeffs= new_coeffs
  File "C:\Python\numInt.py", line 88, in coeffs
    self.coeffs= new_coeffs
  File "C:\Python\numInt.py", line 88, in coeffs
    self.coeffs= new_coeffs
  [Previous line repeated 989 more times]
RecursionError: maximum recursion depth exceeded

这不是任何家庭作业或类似内容的一部分，我只是在努力提高我的 Python 技能。

Answer 1

问题是coeffs 的设置器与__init__ 中的self.coeffs = coeffs 行交互

    @coeffs.setter
    def coeffs(self,new_coeffs):#TAKES IN A LIST
        self.coeffs= new_coeffs

设置coeffs 调用setter，但是setter 在内部再次设置它，导致无限循环。通常（但不是通用的）约定是将“_”附加到支持变量的名称。所以让你的二传手：

    @coeffs.setter
    def coeffs(self,new_coeffs):#TAKES IN A LIST
        self.coeffs_ = new_coeffs # Notice the _

和你的吸气剂

    @property
    def coeffs(self):
        return self.coeffs_

Answer 2

问题解决了！我不知道为什么，但我所做的只是将poly 的__init__() 方法中的self.coeffs 更改为self._coeffs。