Python函数找不到全局变量

Ben Leonard • 3 年前 • 1275 次点击

我正在为Python中的线性回归程序创建一个计算b1的程序。

当试图给b1全局变量赋值时,IDE找不到它。你可以在函数的最后一行找到变量赋值。

x_data = [4, 8, 6, 3, 4, 6, 2, 1, 3]
y_data = [2, 4, 7, 3, 4, 8, 3, 2, 5]
b1 = 0

def b0_b1_calc():
    x_sum = 0
    y_sum = 0
    for i in x_data:
        x_sum += x_data[i]
        y_sum += y_data[i]
    x_mean = round(1, x_sum / len(x_data))
    y_mean = round(1, y_sum / len(y_data))
    x_list = []
    y_list = []
    for i in x_data:
        x_list.append(i - x_mean)
        y_list.append(i - y_mean)
    x_minus_x_squared = []
    for i in x_list:
        x_minus_x_squared.append((x_list[i] - x_mean) ** 2)
    x_sum = sum(x_minus_x_squared)
    x_y = []
    for i in x_data:
        x_y.append(y_list * x_list)
    x_y = sum(x_y)
    b1 = x_y / x_sum
    
print(str(b1))

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1275 次点击

文章 [ 2 ] | 最新文章 3 年前

• 1 楼

Kumar Arnav 3 年前

请申报 b1 像 global 在以下功能中:

    def b0_b1_calc():
       global b1
       # remaining code in the function

• 2 楼

Freddy Mcloughlan 3 年前

你必须使用 global 访问全局变量。代码中还有一些错误,我已经修复并注释了这些错误:

def b0_b1_calc():
    # Use global to access global variables
    global b1

    # sum() summates a list
    x_sum = sum(x_data)
    y_sum = sum(y_data)

    # This was the wrong way around
    x_mean = round(x_sum / len(x_data))
    y_mean = round(y_sum / len(y_data))

    x_list = []  # could also be [i - x_mean for i in x_data]
    y_list = []  # could also be [i - y_mean for i in x_data]

    for i in x_data:
        x_list.append(i - x_mean)
        y_list.append(i - y_mean)

    # could also be [(x_list[i] - x_mean) ** 2 for i in x_list]
    x_minus_x_squared = []

    for i in x_list:
        x_minus_x_squared.append((x_list[i] - x_mean) ** 2)

    x_sum = sum(x_minus_x_squared)
    x_y = []

    for i in x_data:
        # could be simplified to [np.array(y_list) * np.array(x_list) for i in x_data]
        # use np.array for vectorial array multiplication
        x_y.append(np.array(y_list) * np.array(x_list))
    
    x_y = sum(x_y)
    b1 = x_y / x_sum


b0_b1_calc()

绕开环球旅行的首选方式是打电话 return :

def b0_b1_calc():
    # ... code here
    return b1

b1 = b0_b1_calc()

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