为什么我收到“UnboundLocalError 局部变量“coffee_machine”？赋值前引用”尽管 Coffee_machine 是一个全局变量？

发布于 2025-01-09 03:42:23 字数 472 浏览 0 评论 0原文

coffee_machine = True

def user_input():
    while coffee_machine:
            user_choice = input("What type of coffee would you like espresso/latte/cappuccino?")
            if user_choice == "off".lower():
                coffee_machine = False
            x = []
            for ingredients in MENU[user_choice].get("ingredients").values():
                x.append(ingredients)
            print(x)

user_input()

原文

coffee_machine = True

def user_input():
    while coffee_machine:
            user_choice = input("What type of coffee would you like espresso/latte/cappuccino?")
            if user_choice == "off".lower():
                coffee_machine = False
            x = []
            for ingredients in MENU[user_choice].get("ingredients").values():
                x.append(ingredients)
            print(x)

user_input()

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智商已欠费 2025-01-16 03:42:23

您尚未在函数开头声明 global Coffee_machine，因此它不会被强制为全局的，并且在函数内您尝试为其设置一个值，这使其成为本地的。
所需要做的就是添加 global 行，这将强制它成为全局的，如下所示：

coffee_machine = True

def user_input():
    global coffee_machine
    while coffee_machine:
            user_choice = input("What type of coffee would you like espresso/latte/cappuccino?")
            if user_choice == "off".lower():
                coffee_machine = False
            x = []
            for ingredients in MENU[user_choice].get("ingredients").values():
                x.append(ingredients)
            print(x)

user_input()

You have not declared global coffee_machine at the start of the function, and thus it's not forced to be global, and within the function you try setting a value to it, which makes it local.
All that's needed to be done is adding that global line which will force it to be global, like so:

coffee_machine = True

def user_input():
    global coffee_machine
    while coffee_machine:
            user_choice = input("What type of coffee would you like espresso/latte/cappuccino?")
            if user_choice == "off".lower():
                coffee_machine = False
            x = []
            for ingredients in MENU[user_choice].get("ingredients").values():
                x.append(ingredients)
            print(x)

user_input()

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