Python - 如何返回特定行[重复]

Question

我刚开始学习python一周。

我正在尝试做一个测试：

---

"Beginning of the Program"
print("Hi Sir and welcome to my calculator")
print("Please select from the below menu your math operation")

MenuOption = input("+ for Add, - for Subtract, * for Multiply, / for Division: ") 

if (MenuOption != "+" and MenuOption != "-" and MenuOption != "*" and MenuOption != "/"):
    print("You have typed wrong character, please try again")
    **# my problem is here, I want it to loop back to MenuOption  line**

else:
    print("Thanks for the correct selection")



FirstNumber = int(input("First Number: "))
SecondNumber = int(input("Second Number: "))

if (MenuOption == "+"):
    print(FirstNumber + SecondNumber)

elif (MenuOption == "-"):
    print(FirstNumber - SecondNumber)              

elif (MenuOption == "*"):
    print(FirstNumber * SecondNumber)

elif (MenuOption == "/"):
    print(FirstNumber / SecondNumber)

---

当我不按任何数学符号（+、-、*、/）时，我希望程序开始恢复 MenuOption

Answer 1

您需要学习循环。如果您执行while 的操作，循环表达式将变为false，它将正常运行。当将选择其中一个符号+ - / * 时，将某个变量设置为false，否则，flag 变量应为true。

注意

那是因为python 也不支持goto 和label