How to print the first line from a traceback stack

Question

Suppose I am given the following traceback:

Traceback (most recent call last):    
  File "<wingdb_compile>", line 3, in <module>    
  File "C:\Python34\lib\ftplib.py", line 419, in login    
    resp = self.sendcmd('PASS ' + passwd)    
  File "C:\Python34\lib\ftplib.py", line 272, in sendcmd    
    return self.getresp()    
  File "C:\Python34\lib\ftplib.py", line 245, in getresp    
    raise error_perm(resp)    
ftplib.error_perm: 530 Login incorrect.

I have managed to extract the Error details but what has stumped me is how would I extract the line:

File "<wingdb_compile>", line 3, in <module>

I was looking at methods in the trace back package but wondered if any one had experience with that here

Answer 1

The function traceback.format_exc is built primarily for this

This is like print_exc(limit) but returns a string instead of printing to a file.

>>> import traceback
>>> try:
...     x = 2/0
... except:
...     error = traceback.format_exc()
... 
>>> error
'Traceback (most recent call last):\n  File "<stdin>", line 2, in <module>\nZeroDivisionError: division by zero\n'
>>> linesoferror = error.split('\n')
>>> linesoferror
['Traceback (most recent call last):', '  File "<stdin>", line 2, in <module>', 'ZeroDivisionError: division by zero', '']

So now you wanted the first line then you can simply use

>>> linesoferror[1]
'  File "<stdin>", line 2, in <module>'

Voila! You have what you want

ALERT - Valid for Python 2.4.1 and above