你能在 Python 中访问另一个静态变量中的静态变量吗

Question

我正在使用我在它之前的行中初始化的变量，控制台给了我以下错误：

NameError: name 'Purchase' is not defined

这是我抛出此异常的代码

class Purchase:
   list_of_items = ["Cake", "Soap", "Jam", "Cereal", "Hand Sanitizer", "Biscuits", "Bread"]
   list_of_count_of_each_item_sold = [0] * Purchase.list_of_items

我不明白为什么会这样，因为当我在 class 方法中使用静态变量时，从来没有发生过这样的错误吗？

Answer 1

当行 list_of_count_of_each_item_sold = [0] * Purchase.list_of_items 被评估时，作用域已经在 class 内，所以没有必要使用 Purchase.list_of_items。可以直接访问list_of_items:

class Purchase:
    list_of_items = ["Cake", "Soap", "Jam", "Cereal", "Hand Sanitizer", "Biscuits", "Bread"]
    list_of_count_of_each_item_sold = [0] * list_of_items

此外，要为 list_of_items 中的每个项目使用 0 正确初始化 list_of_count_of_each_item_sold，您必须使用 [0] 乘以 list_of_items 的长度len().

class Purchase:
    list_of_items = ["Cake", "Soap", "Jam", "Cereal", "Hand Sanitizer", "Biscuits", "Bread"]
    list_of_count_of_each_item_sold = [0] * len(list_of_items)

你能在 Python 中访问另一个静态变量中的静态变量吗

Can you access a static variable in another static variable in Python

oop

static

nameerror

python-3.x