我正在为大学二年级做准备，在我们被要求做的一项练习中，我有几个与 if 语句相关的问题

我们必须编写一个 Todo 应用程序，有一次练习要求我们用 elif 替换“显示”、“编辑”、“退出”和“完成”的 if 语句

问题是当我尝试用 elif 替换原来的 if 语句时，我的程序根本不起作用

elif语句执行前的代码

prompt = " Add or show  or type exit to quit the programm  or edit to edit a item in your list  : "
list = []

while True:
    useraction = input(prompt + " you can also right  completed to remove an task that you have done ")
    useraction = useraction.strip()
    if "add" in useraction:
        todo = useraction[4:]
        with open("app.txt", "r") as file:
            list = file.readlines()

        list.append(todo)
        with open("app.txt", "w") as file:
            file.writelines(list)

    elif "completed" in useraction:
        num = int(input("Please right the number of the task that is completed"))
        with open("app.txt", "r") as file:
            list = file.readlines()
        list.pop(num - 1)

    print("That task has been completed, congratulation!")

    if "show" in useraction:
        with open("app.txt", "r") as file:
            list = file.readlines()

        for index, item in enumerate(list):
            item = item.strip("\n")
            row = f"{index + 1}-{item}"
            row = row.title()
            print(row)

    if "exit" in useraction:
        break

    if "edit" in useraction:
        number = int(input("please right the number of the item that you want to modify : "))
        number = number - 1

        with open("app.txt", "r") as file:
            list = file.readlines()
        new_todo = input("please right the new thing that you want to do : ")
        list[number] = new_todo
    with open("app.txt", "w") as file:
        file.writelines(list)

print("Bye !")


When i decide to put the elif statement  in the code this is what happen :



prompt = " Add or show  or type exit to quit the programm  or edit to edit a item in your list  : "
list = []

while True:
    useraction = input(prompt + " you can also right  completed to remove an task that you have done ")
    useraction = useraction.strip()
    if "add" in useraction:
        todo = useraction[4:]
        with open("app.txt", "r") as file:
            list = file.readlines()

        list.append(todo)
        with open("app.txt", "w") as file:
            file.writelines(list)

    elif "completed" in useraction:
        num = int(input("Please right the number of the task that is completed"))
        with open("app.txt", "r") as file:
            list = file.readlines()
        list.pop(num - 1)

    print("That task has been completed, congratulation!")

    elif "show" in useraction:
        with open("app.txt", "r") as file:
            list = file.readlines()

        for index, item in enumerate(list):
            item = item.strip("\n")
            row = f"{index + 1}-{item}"
            row = row.title()
            print(row)

    elif "exit" in useraction:
        break

    elif "edit" in useraction:
        number = int(input("please right the number of the item that you want to modify : "))
        number = number - 1

        with open("app.txt", "r") as file:
            list = file.readlines()
        new_todo = input("please right the new thing that you want to do : ")
        list[number] = new_todo
    with open("app.txt", "w") as file:
        file.writelines(list)

print("Bye !")

我有超过 16 个错误，其中大部分与以下相关：

预期声明，发现 Py:ELIF_KEYWORD 变量注释的非法目标预期表达式等…