>>> raise Exception('This is the error message.')

Traceback (most recent call last):

File "<pyshell#191>", line 1, in <module>

raise Exception('This is the error message.')

Exception: This is the error message.

Getting the Traceback as a String:

>>> import traceback

>>> try:

raise Exception('This is the error message.')

except:

errorFile = open('errorInfo.txt', 'w')

errorFile.write(traceback.format_exc())

errorFile.close()

print('The traceback info was written to errorInfo.txt.')

116

The traceback info was written to errorInfo.txt.

Assertions: see it in book.

Logging:

import logging

logging.basicConfig(level=logging.DEBUG, format=' %(asctime)s - %(levelname)s

- %(message)s')

logging.debug() function when we want to print log information.

DEBUG logging.debug() The lowest level.

Used for small details.

Usually you care about these messages only when diagnosing problems.

INFO logging.info() Used to record information on general events in your program or confirm that things are working at their point in the program.

WARNING logging.warning() Used to indicate a potential problem that doesn’t prevent the program from working but might do so in the future.

ERROR logging.error() Used to record an error that caused the program to fail to do something.

CRITICAL logging.critical() The highest level. Used to indicate a fatal error that has caused or is about to cause the program to stop running entirely.

>>> import logging

>>> logging.basicConfig(level=logging.DEBUG, format=' %(asctime)s -

%(levelname)s - %(message)s')

>>> logging.debug('Some debugging details.')

2015-05-18 19:04:26,901 - DEBUG - Some debugging details.

>>> logging.info('The logging module is working.')

2015-05-18 19:04:35,569 - INFO - The logging module is working.

>>> logging.warning('An error message is about to be logged.')

2015-05-18 19:04:56,843 - WARNING - An error message is about to be logged.

>>> logging.error('An error has occurred.')

2015-05-18 19:05:07,737 - ERROR - An error has occurred.

>>> logging.critical('The program is unable to recover!')

2015-05-18 19:05:45,794 - CRITICAL - The program is unable to recover!

Disabling Logging:

>>> import logging

>>> logging.basicConfig(level=logging.INFO, format=' %(asctime)s -

%(levelname)s - %(message)s')

>>> logging.critical('Critical error! Critical error!')

2015-05-22 11:10:48,054 - CRITICAL - Critical error! Critical error!

>>> logging.disable(logging.CRITICAL)

>>> logging.critical('Critical error! Critical error!')

>>> logging.error('Error! Error!')