基本python计算器中的函数出现问题，不确定如何修复

我对编程相当陌生，想做一个简单的计算器作为练习，但我似乎无法得到一个函数以我想要的方式工作，我确信这是因为我遗漏了一些东西，但我不确定到底是什么。我试图寻找一些答案，但我要么不太理解，要么不知道如何实现它。在我编写的代码中，如果我删除ask（）并将其替换为我定义为的代码，它会工作，但当我使用ask（）时，它不会工作，并给出一个错误，指出“未定义名称“x”。任何帮助，以及任何提示或方法，我可以改善这一点表示感谢。提前谢谢

    def Add(x, y):
        print("Adding %d and %d" % (x, y))
        print("Answer:", x + y)

    def Subtract(x, y):
        print("Subtracting %d from %d" % (y, x))
        print("Answer:", x - y)

    def Multiply(x, y):
        print("Multiplying %d and %d" % (x, y))
        print("Answer:", x * y)

    def Divide(x, y):
        print("Dividing %d from %d" % (y, x))
        print("Answer:", x / y)

    def ask():
         print("Which two numbers would you like to use?")
         x = input(">")
         y = input(">")

    print("Would you like to (a)dd, (s)ubtract, (m)ultiply, or (d)ivide two numbers?")

    op = input(">")

    if op == "a":
        ask()
        Add(x, y)

    elif op == "s":
        ask()
        Subtract(x, y)

    elif op == "m":
        ask()
        Multiply(x, y)

    elif op == "d":
        ask()
        Divide(x, y)

     else:
         print("I don't know what that means.")
         print("\n")

---

您应该返回这些值，还应该将它们转换为

float

或任何您想要的值，以便对它们执行数字运算

def ask():
     print("Which two numbers would you like to use?")
     x = float(input(">"))
     y = float(input(">"))
     return (x,y)

然后可以从函数中获取返回的值，如

if op == "a":
    x,y = ask()
    Add(x, y)

---

除了你手头的问题之外，我能提出一些建议吗

---

在处理之前，需要将用户输入解析为int。另外，

ask

需要返回用户输入。虽然这比您可能想要的要多，但希望您可以将其用作进一步编码的模板。感谢您的帮助和建议，我以后一定会记住这些。这是一个很好的解决方案，但您应该解释为什么必须这样做。

# use these as templates
str_fun_cal = "{}: {} with {}"
str_res = "Answer: {}"

# Look at the cleanliness of this!!!!
# Also these actually do what they say they do instead of just printing the result out.  Useful for further
# functionality
def Add(x, y):
    return x + y

def Subtract(x, y):
    return x - y

def Multiply(x, y):
    return x * y

def Divide(x, y):
    return x / y

# use a dictionary to select the function the user calls
func_call_dict = {'a':Add, 's':Subtract, 'm':Multiply, 'd':Divide}

# Fixed an issue with not returning any values
def ask():
    print("Which two numbers would you like to use?")
    in_x = float(input(">"))
    in_y = float(input(">"))
    return in_x, in_y

# Printing function to clean things up
def print_fun(fun_call, x, y, res):
    print(str_fun_cal.format(fun_call, x, y))
    print(str_res.format(res))

print("Would you like to (a)dd, (s)ubtract, (m)ultiply, or (d)ivide two numbers?")
op = input(">")

# check to see if in dictionary, if so then execute the corresponding function if not, display error
if op in func_call_dict:
    x, y = ask()
    sel_fun = func_call_dict[op]
    calc_val = sel_fun(x, y)
    print_fun(sel_fun.__name__, x, y, calc_val) # use of `.__name__` returns the name of the function (Add, Subtract, etc,.) 

else:
    print("I don't know what that means.")
    print("\n")