如何追溯函數內引發異常的原因？

Question

（這是一個後續問題到柱Python try/except: Showing the cause of the error after displaying my variables。）

我有以下script.py：

import traceback 


def process_string(s): 
    """ 
    INPUT 
    ----- 
    s: string 

     Must be convertable to a float 

    OUTPUT 
    ------ 
    x: float 
    """ 

    # validate that s is convertable to a float 
    try: 
     x = float(s) 
     return x 
    except ValueError:   
     print 
     traceback.print_exc() 


if __name__ == '__main__': 

    a = process_string('0.25') 
    b = process_string('t01') 
    c = process_string('201') 

在的script.py執行，下面的消息被打印在終端窗口：

Traceback (most recent call last): 
    File "/home/user/Desktop/script.py", line 20, in process_string 
    x = float(s) 
ValueError: could not convert string to float: t01 

請問是否有方法讓traceback.print_exc()也在終端窗口打印if-main裏面的哪個指令拋出了ca除了try-except從句嗎？

Answer 1

這是怎麼回事？

import traceback 


def process_string(s): 
    """ 
    INPUT 
    ----- 
    s: string 

     Must be convertible to a float 

    OUTPUT 
    ------ 
    x: float 
    """ 
    return float(s) 



if __name__ == '__main__': 
    try: 
     a = process_string('0.25') 
     b = process_string('t01') 
     c = process_string('201') 
    except ValueError:   
     print 
     traceback.print_exc()