变量“result”未定义

Question

我一直在写这段代码，每次我运行它它都会说结果没有定义。在

Error: Traceback (most recent call last):
  File "/Users/Bubba/Documents/Jamison's School Work/Programming/Python scripts/Ch9Lab2.py", line 24, in <module>
    print(str(numberOne) + " " + operation + " " + str(numberTwo) + " = " + str(result))
NameError: name 'result' is not defined

原代码：

^{pr2}$

Answer 1

变量“result”只在函数的作用域中定义。如果要打印出来，应该将performOperation函数的结果赋给result变量。另外，确保在函数中实际返回了一些内容。在

def performOperation(numberOne, numberTwo):
    if operation == "+":
        result = numberOne + numberTwo
    if operation == "-":
        result = numberOne - numberTwo
    if operation == "*":
        result = numberOne * numberTwo
    if operation == "/":
        result = numberOne / numberTwo
    return result

result = performOperation(numberOne, numberTwo)
print str(result) # will print the result

Answer 2

您需要使用return关键字在函数外部使用变量result

def performOperation(numberOne, numberTwo):
    ...
    return result

result = performOperation(numberOne, numberTwo)