python - Why exc_traceback returns None -

sys.exc_info() returns tuple (type , value, traceback).
sys.exc_info()[2] our traceback object.

why not catch exceptions traceback code:

import sys  try:     1/0 except zerodivisionerror:     print sys.exc_info()[2].tb_frame.f_back

tb_frame , f_back usage has been explained here: frame objects

you see none because there no outer frame. you're executing directly, current frame last frame. demonstrate this, created demo.py:

import sys  try:     1/0 except zerodivisionerror:     print sys.exc_info()[2].tb_frame.f_back

which should familiar, , trivial caller.py:

import demo

now see difference:

$ python demo.py none  $ python caller.py <frame object @ 0x10bc34c20>

in second case, there outer frame (i.e. caller.py), don't see none.

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