IPythonのデバッガー(ipdb)の使い方

This is a copy of Debugging with ipython and ipdb.

Debugging with ipython and ipdb

Make sure you have setuptools installed

• http://pypi.python.org/pypi/setuptools/
• Try to run which easy_install
• Should return something like: /usr/local/share/python/easy_install

Install ipython and ipdb

• sudo easy_install ipython
• sudo easy_install ipdb
• Windows installers can be found here:
  • http://pypi.python.org/pypi/ipython
  • also install pyreadline: http://pypi.python.org/pypi/pyreadline/1.7.1

Place a breakpoint in your code

print 'Hello World!'
my_var = 10 / 3
import ipdb; ipdb.set_trace() # BREAKPOINT
print my_var

Run your code

python my_project.py

Use ipdb

• ? for "help"
• ? s for "help for command s"
• l for "some more context"
• s for "step into"
• n for "step over"
• c for "continue to next breakpoint"

Sample program with a bug

• http://bit.ly/buggy-class
• Download "buggy.py"
• Run the program:
  • python buggy.py Django
• It should return the version of Django
• But it does not
• Place a breakpoint at line 45
• Step through it and fix it :)

Hint: Use pprint

• import pprint
• pprint.pprint(some_variable)