Hints, tips and tricks in python

Creating a simple webserver

To create a simple webserver:

Python 2:

python -m SimpleHTTPServer 7777

Python 3:

python -m http.server 7777

Vendo os atributos de um objeto

Seguindo a dica do StackOverflow conseguimos ver os atributos e respectivos valores de qualquer obejto em python:

for attr, value in objeto.__dict__.iteritems():
    print attr, value

Solving AttributeError: 'module' object has no attribute 'packaging'

To the "AttributeError: 'module' object has no attribute 'packaging'" error I did as stated here:

1. Start a python session, import pkg_resources, and view the file from which it is loaded:

   In [1]: import pkg_resources

   In [2]: pkg_resources.file Out[2]: '/usr/lib/python2.7/dist-packages/pkg_resources.pyc'

2. Remove this file (and the associated *.py file):

   $ sudo rm /usr/lib/python2.7/dist-packages/pkg_resources.py*

Locating the line number of an exception

From this answer in StackOverflow:

import traceback
import sys

try:
    raise Exception("foo")
except:
    for frame in traceback.extract_tb(sys.exc_info()[2]):
        fname,lineno,fn,text = frame
        print "Error in %s on line %d" % (fname, lineno)

Working with VirtualEnv

Withe the help of Virtual Environments — The Hitchhiker's Guide to Python:

Install virtualenv first with:

sudo pip install virtualenv

Then create and use a virtual environment for the project:

cd project
virtualenv venv
source venv/bin/activate
pip install -r requirements.txt
# Do what you have to do
deactivate