python之如何解决 UnboundLocalError

我刚开始编程并尝试写一些东西但(当然)它失败了。在我找到真正的问题之后:UnboundLocalError。因此，为了让您远离周围的所有废墟，我将代码简化为:

def test(): 
    try: 
        i1 = int(i1) 
        i2 = int(i2) 
    except ValueError: 
        print "you failed in typing a number" 
 
def input():  
    i1 = raw_input('please type a number \n >') 
    i2 = raw_input('please type a number \n >') 

然后我写下:

>>>input() 
please insert a number 
> 3 
please insert a number 
> 2  
>>>test() 

然后我得到:

that was not a number 
Traceback (most recent call last): 
  File "<stdin>", line 1, in <module> 
  File "<stdin>", line 7, in test 
UnboundLocalError: local variable 'i1' referenced before assignment 

我怎样才能用 Pythonic 的方式解决这个问题？还是我应该采取完全不同的方式？

请您参考如下方法:

执行此操作的最标准方法是为您的测试方法提供参数:

def test(i1, i2): 
    try: 
        i1 = int(i1) 
        i2 = int(i2) 
    except ValueError: 
        print "you failed in typing a number" 
 
def input():  
    i1 = raw_input('please type a number \n >') 
    i2 = raw_input('please type a number \n >') 
    test(i1, i2)   # here we call directly test() with entered "numbers" 

如果你真的想在交互式提示上进行测试，你可以这样做(如@FerdinandBeyer 评论中所建议的那样):

def test(i1, i2): 
    try: 
        i1 = int(i1) 
        i2 = int(i2) 
    except ValueError: 
        print "you failed in typing a number" 
    return i1, i2 
     
def input():  
    i1 = raw_input('please type a number \n >') 
    i2 = raw_input('please type a number \n >') 
    return i1, i2 

然后，根据提示:

>>>var1, var2 = input() 
please insert a number 
> 3 
please insert a number 
> 2  
>>>test(var1, var2)