python - 在我的 Python 应用程序中找不到名称

Question

keepProgramRunning = True

while keepProgramRunning:
    print "Welcome to the Calculator!"
    print "Please choose what you'd like to do:"

    print "0: Addition"
    print "1: Subtraction"
    print "2: Multiplication"
    print "3: Division"    


    #Capture the menu choice.
    choice = raw_input()

    #Capture the numbers you want to work with.
    numberA = raw_input("Enter your first number: ")
    numberB = raw_input("Enter your second number: ")

    if choice == "0":
        print "Your result is:"
        print Addition(numberA, numberB)
    elif choice == "1":
        print "Your result is:"
        print Subtraction(numberA, numberB)
    elif choice == "2":
        print "Your result is:"
        print Multiplication(numberA, numberB)
    elif choice == "3":
        print "Your result is:"
        print Division(numberA, numberB)
    else:
        print "Please choose a valid option."



def Addition(a, b):
    return a + b

def Subtraction(a, b):
    return a - b

def Multiplication(a, b):
    return a * b

def Division(a, b):
    return a / b

这是错误:

Traceback (most recent call last):
  File "C:\Users\Sergio.Tapia\Documents\NetBeansProjects\Tutorials\src\tutorials.py", line 23, in <module>
    print Addition(numberA, numberB)
NameError: name 'Addition' is not defined

感谢您的帮助!

附言。我意识到循环永远不会结束，我还没有添加菜单选项。 :P

Answer 1

您需要在调用函数之前定义它们。

当解释器读取调用 Addition() 的行时，它还没有到达定义 Addition() 的行。因此它会抛出异常。