需要帮助从 python 中的另一个类调用函数

Question

我写了一个简单的单位转换器程序。在 main() 类中，我有一个基本程序，要求用户选择要使用的转换器。然后我为每个转换器编写了一个特定的类。我想做的是将每个转换器方法导入 main.说实话，我不确定我是否需要 main()。无论如何，所有类都有效，我只是不知道如何将方法导入到它们适当的占位符中。我希望这是有道理的。

print("Welcome to the Amazing Converter!\n")

def main():

    print("[1] Convert Temperature")
    print("[2] Convert Distance")
    print("[3] Convert Weight")

    again = True
    while True:
        try:
            choice = int(input("What would you like to convert? "))
        except ValueError:
            print("Invalid entry.")
        
        if choice == 1:
            print("[1] Convert from Celsius to Farenheit")
            print("[2] Convert from Farenheit to Celsius")
            temp_choice = int(input("Enter your choice: "))

            if temp_choice == 1:
                pass
            elif choice == 2:
                pass
                    
        elif choice == 2:
            print("[1] Convert from Miles to Kilometers")
            print("[2] Convert from Kilometers to Miles")
            dist_choice = int(input("Enter your choice: "))

            if dist_choice == 1:
                pass            
            elif dist_choice == 2:
                pass
            
        elif choice == 3:
            print("[1] Convert from Pounds to Kilos")
            print("[2] Convert from Kilos to Pounds")
            weight_choice = int(input("Enter your choice: "))

            if weight_choice == 1:
                pass
            elif weight_choice == 2:
                pass   

        again = input("Would you like to Convert another unit of measurement? ")
        if again == 1:
            True
        else:
            print("Have a good day!")
            break

if __name__ == "__main__":
    main()




#Convert Celsius to Farenheit
class Temperature:
    temp = 0
    def __init__(self, temp):
        self.temp = temp

    def cel_to_far(self):
        res = (self.temp * 9/5) + 32
        return res

celsius = float(input("Enter celsius value: "))  
far_temp = Temperature(celsius)
print(round(far_temp.cel_to_far()))



#Convert Farenheit to Celsius
class Temperature:
    temp = 0
    def __init__(self, temp):
        self.temp = temp

    def far_to_cel(self):
        res = (self.temp - 32) * 5/9
        return res

farenheit = float(input("Enter farenheit value: "))  
cel_temp = Temperature(farenheit)
print(round(cel_temp.far_to_cel()))


#Convert miles to kilometers
class Distance:
    dist = 0
    def __init__(self, dist):
        self.dist = dist

    def mil_to_kil(self):
        res = (self.dist * 1.609344)
        return res

miles = float(input("Enter mile value: "))
miles_dist = Distance(miles)
print(round(miles_dist.mil_to_kil()))



#Convert kilometers to miles
class Distance:
    dist = 0
    def __init__(self, dist):
        self.dist = dist

    def kil_to_mil(self):
        res = (self.dist * 0.62137)
        return res

kilometers = float(input("Enter kilometer value: "))
kilo_dist = Distance(kilometers)
print(round(kilo_dist.kil_to_mil()))


#Convert pounds to kilos
class Weight:
    def __init__(self, weight):
        self.weight = weight

    def pound_to_kilo(self):
        res = (self.weight * 0.45359237)
        return res

pounds = float(input("Enter pound value: "))
pound_weight = Weight(pounds)
print(round(pound_weight.pound_to_kilo()))


#Convert kilos to pounds
class Weight:
    def __init__(self, weight):
        self.weight = weight

    def kilo_to_pound(self):
        res = (self.weight / 0.45359237)
        return res

kilos = float(input("Enter kilo value: "))
kilo_weight = Weight(kilos)
print(round(kilo_weight.kilo_to_pound()))

Answer 1

您创建的重复类。所以让他们更容易像

class Temperature:
    
    def cel_to_far(self, temp):
        res = (temp * 9/5) + 32
        return res

    def far_to_cel(self, temp):
        res = (temp - 32) * 5/9
        return res

并为该类创建对象，像这样

def main():
    
    # creating object
    temperature = Temperature()

并且调用温度方法就像

        if choice == 1:
            print("[1] Convert from Celsius to Farenheit")
            print("[2] Convert from Farenheit to Celsius")
            temp_choice = int(input("Enter your choice: "))

            if temp_choice == 1:   
                celsius = float(input("Enter celsius value: "))  
                print(round(temperature.cel_to_far(celsius)))
            elif choice == 2:
                farenheit = float(input("Enter farenheit value: "))  
                print(round(temperature.far_to_cel(farenheit)))

希望，你明白了。

Answer 2

您已经在每个类下面提供了如何使用该类的示例。例如，在定义 Temperature 类的位置下方，您有：

celsius = float(input("Enter celsius value: "))  
far_temp = Temperature(celsius)
print(round(far_temp.cel_to_far()))

您需要做的是将这些移动到您想要使用它们的main 的相关部分。例如你有：

            if temp_choice == 1:
                pass

你可以用它（适当缩进）代替pass。

            if temp_choice == 1:
                celsius = float(input("Enter celsius value: "))  
                far_temp = Temperature(celsius)
                print(round(far_temp.cel_to_far()))

但是，你需要做的另一件事是移动调用main的代码，即：

if __name__ == "__main__":
    main()

在定义其他类之后到模块的末尾。

如果你现在尝试它，你会得到一个NameError，因为在调用main 时还没有定义其他类。

事实上你并不需要

if __name__ == "__main__":

除非您也可以将您的模块导入另一个模块。如果您知道您只会将其直接作为主程序运行 (python your_module.py)，那么只需将 main() 放在末尾即可。

最后，您的转换类似乎是两个方向的温度具有相同的名称（都称为Temperature）。虽然您可以重命名它们以避免名称冲突，但它们实际上是一种适合合并到具有 cel_to_far 和 far_to_cel 方法的单个类的形式，对于其他类也是如此。

把所有这些放在一起（并删除关于重复“你想转换另一个单位吗？”这超出了这个问题的范围），代码看起来像这样：

print("Welcome to the Amazing Converter!\n")

def main():

    print("[1] Convert Temperature")
    print("[2] Convert Distance")
    print("[3] Convert Weight")

    again = True
    while True:
        try:
            choice = int(input("What would you like to convert? "))
        except ValueError:
            print("Invalid entry.")
        
        if choice == 1:
            print("[1] Convert from Celsius to Farenheit")
            print("[2] Convert from Farenheit to Celsius")
            temp_choice = int(input("Enter your choice: "))

            if temp_choice == 1:
                celsius = float(input("Enter celsius value: "))  
                far_temp = Temperature(celsius)
                print(round(far_temp.cel_to_far()))
            elif temp_choice == 2:
                farenheit = float(input("Enter farenheit value: "))  
                cel_temp = Temperature(farenheit)
                print(round(cel_temp.far_to_cel()))
                    
        elif choice == 2:
            print("[1] Convert from Miles to Kilometers")
            print("[2] Convert from Kilometers to Miles")
            dist_choice = int(input("Enter your choice: "))

            if dist_choice == 1:
                miles = float(input("Enter mile value: "))
                miles_dist = Distance(miles)
                print(round(miles_dist.mil_to_kil()))

            elif dist_choice == 2:
                kilometers = float(input("Enter kilometer value: "))
                kilo_dist = Distance(kilometers)
                print(round(kilo_dist.kil_to_mil()))
            
        elif choice == 3:
            print("[1] Convert from Pounds to Kilos")
            print("[2] Convert from Kilos to Pounds")
            weight_choice = int(input("Enter your choice: "))

            if weight_choice == 1:
                pounds = float(input("Enter pound value: "))
                pound_weight = Weight(pounds)
                print(round(pound_weight.pound_to_kilo()))
            elif weight_choice == 2:
                kilos = float(input("Enter kilo value: "))
                kilo_weight = Weight(kilos)
                print(round(kilo_weight.kilo_to_pound()))


class Temperature:
    temp = 0
    def __init__(self, temp):
        self.temp = temp

    def cel_to_far(self):
        res = (self.temp * 9/5) + 32
        return res

    def far_to_cel(self):
        res = (self.temp - 32) * 5/9
        return res


class Distance:
    dist = 0
    def __init__(self, dist):
        self.dist = dist

    def mil_to_kil(self):
        res = (self.dist * 1.609344)
        return res

    def kil_to_mil(self):
        res = (self.dist * 0.62137)
        return res


class Weight:
    def __init__(self, weight):
        self.weight = weight

    def pound_to_kilo(self):
        res = (self.weight * 0.45359237)
        return res

    def kilo_to_pound(self):
        res = (self.weight / 0.45359237)
        return res


main()