调用和打印课程时遇到问题

Question

我正在做一个家庭作业，我们正在创建一个用于程序的类，用于单独或全部计算一次进行基本数学计算。所以加，减，乘，除或全四。

我认为大部分代码都很好，但是在用户输入数字并选择了一个插值方法之后我无法打印它。我试过print（Week7.addNum），print（Week7.addNum（）），print（Week7.addnum（numOne，numTwo））。我得到各种错误或没有。随着印刷品（Week7.addnum），我得到了。我只是在研究添加功能，并想知道如果我可以让其他人跟着工作。

class Week7:

    def __init__(self, numOne, numTwo):
        self.numOne = numOne
        self.numTwo = numTwo

    def addNum(self):
        return (self.numOne + self.numTwo)

    def subtNum(self):
        return (self.numOne - self.numTwo)

    def multNum(self):
        return (self.numOne * self.numTwo)

    def divNum(self):
        if self.numTwo !=0:
            return (self.numOne / self.numTwo)
        else:
            return print('You can not divde by 0')

    def allNum(self):
        return (self.numOne + self.numTwo, self.numOne - self.numTwo,     self.numOne * self.numTwo, self.numOne / self.numTwo )



numOne=int(input("Enter first number: "))
numTwo=int(input("Enter second number: "))
functions = [ "1) Add two numbers",
          "2) Mult two numbers",
          "3) Divide two numbers",
          "4) Subtract two numbers",
          "5) All in one: Perform all math Operations",
          "6) End Program" 
        ]
for x in functions:                  
      print( x )
print()


which_Function = int(input("Please select what operation you would like to perform: ") )



if which_Function == 1:
     print(Week7.addNum)

elif which_Function == 2:
     Week7.subtNum(self)

elif which_Function == 3:
     Week7.multNum(self)

elif which_Function == 4:
     Week7.divNum(self)

elif which_Function == 5:
     Week7.allNum(self)

elif which_Function == 6:
     exit

我认为一切都有效，除了问题的实际打印。我想以“1 + 2 = 3”为例。我知道我需要在打印输出中加上“+”和“=”，但我可以弄清楚一旦打印出来的话。提前致谢。戴夫

Answer 1

编辑的代码，应该工作：

class Week7:

    def __init__(self, numOne, numTwo):
        self.numOne = numOne
        self.numTwo = numTwo

    def addNum(self):
        return (self.numOne + self.numTwo)

    def subtNum(self):
        return (self.numOne - self.numTwo)

    def multNum(self):
        return (self.numOne * self.numTwo)

    def divNum(self):
        if self.numTwo !=0:
            return (self.numOne / self.numTwo)
        else:
            return print('You can not divde by 0')

    def allNum(self):
        return (self.numOne + self.numTwo, self.numOne - self.numTwo,     self.numOne * self.numTwo, self.numOne / self.numTwo )



numOne=int(input("Enter first number: "))
numTwo=int(input("Enter second number: "))

w7 = Week7(numOne, numTwo)

functions = [ "1) Add two numbers",
          "2) Mult two numbers",
          "3) Divide two numbers",
          "4) Subtract two numbers",
          "5) All in one: Perform all math Operations",
          "6) End Program" 
        ]
for x in functions:                  
      print( x )
print()


which_Function = int(input("Please select what operation you would like to perform: ") )



if which_Function == 1:
     print(w7.addNum())

elif which_Function == 2:
     print(w7.multNum())

elif which_Function == 3:
     print(w7.divNum())

elif which_Function == 4:
     print(w7.subtNum())

elif which_Function == 5:
     print(w7.allNum())

elif which_Function == 6:
     exit()

---

变更说明：

• w7 = Week7(numOne, numTwo)创建Week7对象的实例
• print(w7.addNum())调用该函数并打印输出。
• --ditto--mult-----等

我也更改了订单，因为它与显示的内容无关。

Answer 2

您需要创建类的实例。尝试类似的东西：

instance = Week7(numOne, numTwo)

if which_Function == 1:
   print(instance.addNum())

elif which_Function == 2:
   print(instance.subtNum())

...

我命名为instance的对象将作为self传递给方法，因为它是你所称的它们。当你查找instance.addNum时，你会得到一个“绑定方法”对象，它会自动为你传递参数。