PyCharm中执行carstuff命令时误调用Python内置help菜单而非自定义帮助菜单

问题根源 #

• 类内方法调用错误：你在askCommand方法中直接执行help()，默认调用的是Python全局内置的帮助工具，而非你在Commands类中定义的自定义help实例方法，调用类内实例方法需要加self.前缀。
• 类方法调用逻辑错误：你在main.py中直接用Commands.askCommand(Commands)调用类方法的写法不符合面向对象规范，需要先实例化Commands类得到实例对象，再通过实例调用方法。

修复步骤 #

1. 修改commands.py文件 #

调整方法调用逻辑，删除类定义下多余的pass：

class Commands:
    def askCommand(self):
        command = input("Enter command:  ")
        if command == "carstuff":
            # 改为调用自身的自定义help方法
            self.help()
        elif command == "sell":
            pass
        elif command == "addcar":
            pass

    def help(self):
        print(
            "carstuff: Brings up the help menu\nsell: Sells the current car\naddcar: Adds another car"
        )

2. 修改main.py文件的调用逻辑 #

先实例化Commands类再调用实例方法：

from car import Car
from commands import Commands


print("Welcome to Craigslist on the command line! Start by entering your car info below.")

brand = input("Enter your car brand: ")
model = input("Enter your car model: ")
year = input("Enter your car's year: ")
condition = input("Enter your car's condition: ")

car = Car(brand, model, year, condition)

print("Your car's price is: " + str(car.price))

print("Now that you've listed your car, you can use commands now!\n")
# 先实例化再调用方法
cmd_instance = Commands()
cmd_instance.askCommand()

可选：修复car.py中的潜在问题 #

你当前的car.py存在几处逻辑错误，后续开发到对应功能时可以同步修改：

class Car:
    def __init__(self, brand, model, year, condition):
        self.brand = brand
        self.model = model
        self.year = year
        self.condition = condition
        self.price = len(model) * 0.75 * 3000
        if self.condition == "Bad":
            # 原写法只做了运算没赋值给price
            self.price -= 100
        elif self.condition == "Brand New":
            self.price += 100

    def Sell(self):
        sure = input("Are you sure you want to sell? (Y/N): ")
        # 原or判断逻辑错误，要分别判断变量的值
        if sure == "Y" or sure == "y":
            self.sellprice = self.price % 75
            # 数字不能直接和字符串拼接，要转成str
            print("You got " + str(self.sellprice) + " from this car.")
        elif sure == "N" or sure == "n":
            print("Sell cancelled.\n")

内容的提问来源于stack exchange，提问作者kooljcid