Python说我的类没有__call__方法

Question

我完全卡住了。以为我已经理解了课程，猜测我错了：/无论如何，我的代码看起来像这样：

class LinearRegression:

def __init__(self, x, y, full = 0):
    self.full = full
    self.x = x
    self.y = y

def __call__(self):
    squared_sum_x = (sum(self.x))**2 
    n = len(self.x)
    xx = sum([item**2 for item in self.x])
    xy = sum([xi*yi for xi, yi in zip(self.x,self.y)])
    a = 1.0*((n*xy -(sum(self.y)*sum(self.x)))/(n*xx - squared_sum_x))
    b = (sum(self.y) - a*sum(self.x))/n
    if self.full == 0:
        return (a,b)
    elif self.full == 1:
        squared_sum_y = (sum(self.y))**2
        yy = sum([item**2 for item in self.y])
        R = float((n*xy -(sum(self.y)*sum(self.x)))/(((n*xx - squared_sum_x)*(n*yy - squared_sum_y))**0.5))
        S_a = (1/(n-2))*((yy-(a*xy)-(b*sum(self.y)))/(xx-(n*xx)))
        S_b = S_a * (n*xx)
        return (a, b, R, S_a, S_b)
    else:
        return "full parameter must be 0, 1 or empty"

lr = LinearRegression(range(10),range(10,30,2),0)
lr()

我收到了以下错误：

AttributeError: LinearRegression instance has no __call__ method

问题是：为什么？因为我花了几个小时分析这段代码，完全不知道错误是什么......

Answer 1

我认为问题出在你的缩进中。你实际上并没有在你的班级中包含这些方法，因为你的缩进是将它们放在＆＃34;外面＆＃34;。试试这个：

class LinearRegression:

    def __init__(self, x, y, full = 0):
        self.full = full
        self.x = x
        self.y = y

    def __call__(self):
        squared_sum_x = (sum(self.x))**2 
        n = len(self.x)
        xx = sum([item**2 for item in self.x])
        xy = sum([xi*yi for xi, yi in zip(self.x,self.y)])
        a = 1.0*((n*xy -(sum(self.y)*sum(self.x)))/(n*xx - squared_sum_x))
        b = (sum(self.y) - a*sum(self.x))/n
        if self.full == 0:
            return (a,b)
        elif self.full == 1:
            squared_sum_y = (sum(self.y))**2
            yy = sum([item**2 for item in self.y])
            R = float((n*xy -(sum(self.y)*sum(self.x)))/(((n*xx - squared_sum_x)*(n*yy - squared_sum_y))**0.5))
            S_a = (1/(n-2))*((yy-(a*xy)-(b*sum(self.y)))/(xx-(n*xx)))
            S_b = S_a * (n*xx)
            return (a, b, R, S_a, S_b)
        else:
            return "full parameter must be 0, 1 or empty"

这种方法将是＆＃34;内部＆＃34;你的班级，而不是独立定义的职能。