e printStackTrace equivalent in python

Question

I know that print e   where e is an Exception  prints the occurred exception but  I was trying to find the python equivalent of Java s e printStackTrace   that exactly traces the exception to what line it occurred and prints the entire trace of it   Could anyone please tell me the equivalent of e printStackTrace   in Python

User · Accepted Answer

import traceback traceback print exc     When doing this inside an except      block it will automatically use the current exception  See http   docs python org library traceback html for more information

User · Answer

There is also logging exception   import logging       try      g   except Exception as ex      logging exception  Something awful happened          will print this message followed by traceback   Output   ERROR 2007-09-18 23 30 19 913 error 1294 Something awful happened  Traceback  most recent call last     File  b py   line 22  in f     g     File  b py   line 14  in g     1 0 ZeroDivisionError  integer division or modulo by zero    From http   blog tplus1 com index php 2007 09 28 the-python-logging-module-is-much-better-than-print-statements  via How to print the full traceback without halting the program

User · Answer

e printStackTrace equivalent in python   In Java  this does the following  docs     public void printStackTrace         Prints this throwable and its backtrace to the standard error stream      This is used like this   try       code that may raise an error   catch  IOException e       exception handling e printStackTrace        In Java  the Standard Error stream is unbuffered so that output arrives immediately   The same semantics in Python 2 are   import traceback import sys try    code that may raise an error     pass  except IOError as e    exception handling       in Python 2  stderr is also unbuffered     print  gt  gt  sys stderr  traceback format exc         in Python 2  you can also from   future   import print function     print traceback format exc    file sys stderr        or as the top answer here demonstrates  use      traceback print exc         which also uses stderr    Python 3  In Python 3  we can get the traceback directly from the exception object  which likely behaves better for threaded code   Also  stderr is line-buffered  but the print function gets  a flush argument  so this would be immediately printed to stderr        print traceback format exception None     lt - type e  by docs  but ignored                                       e  e   traceback               file sys stderr  flush True    Conclusion   In Python 3  therefore  traceback print exc    although it uses sys stderr by default  would buffer the output  and you may possibly lose it  So to get as equivalent semantics as possible  in Python 3  use print with flush True

User · Answer

Adding to the other great answers  we can use the Python logging library s debug    info    warning    error    and critical   methods   Quoting from the docs for Python 3 7 4       There are three keyword arguments in kwargs which are inspected  exc info which  if it does not evaluate as false  causes exception information to be added to the logging message    What this means is  you can use the Python logging library to output a debug    or other type of message  and the logging library will include the stack trace in its output   With this in mind  we can do the following   import logging  logger   logging getLogger   logger setLevel logging DEBUG   def f        a      foo   None         the following line will raise KeyError     b   a  bar    def g        f    try      g   except Exception as e      logger error str e   exc info True    And it will output    bar  Traceback  most recent call last     File   lt ipython-input-2-8ae09e08766b gt    line 18  in  lt module gt      g     File   lt ipython-input-2-8ae09e08766b gt    line 14  in g     f     File   lt ipython-input-2-8ae09e08766b gt    line 10  in f     b   a  bar   KeyError   bar

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