# virtual environment with virtualenvwrapper

Suppose you need to work on three different projects project A, project B and project C. project A and project B need python 3 and some required libraries. But for project C you need python 2.7 and dependent libraries.

So best practice for this is to separate those project environments. To create virtual environment you can use below technique:

Virtualenv, Virtualenvwrapper and Conda

Although we hav several options for virtual environment but virtualenvwrapper is most recommended.

# Create virtual environment with virtualenvwrapper

Suppose you need to work on three different projects project A, project B and project C. project A and project B need python 3 and some required libraries. But for project C you need python 2.7 and dependent libraries.

So best practice for this is to separate those project environments. To create virtual environment you can use below technique:

Virtualenv, Virtualenvwrapper and Conda

Although we have several options for virtual environment but virtualenvwrapper is most recommended.

Although we have several options for virtual environment but I always prefer virtualenvwrapper because it has more facility then others.

$ pip install virtualenvwrapper

$ export WORKON_HOME=~/Envs
$ mkdir -p $WORKON_HOME
$ source /usr/local/bin/virtualenvwrapper.sh
$ printf '\n%s\n%s\n%s' '# virtualenv' 'export WORKON_HOME=~/virtualenvs' 'source /home/salayhin/bin/virtualenvwrapper.sh' >> ~/.bashrc
$ source ~/.bashrc

$ mkvirtualenv python_3.5
Installing
setuptools..........................................
....................................................
....................................................
...............................done.
virtualenvwrapper.user_scripts Creating /Users/salayhin/Envs/python_3.5/bin/predeactivate
virtualenvwrapper.user_scripts Creating /Users/salayhin/Envs/python_3.5/bin/postdeactivate
virtualenvwrapper.user_scripts Creating /Users/salayhin/Envs/python_3.5/bin/preactivate
virtualenvwrapper.user_scripts Creating /Users/salayhin/Envs/python_3.5/bin/postactivate New python executable in python_3.5/bin/python

(python_3.5)$ ls $WORKON_HOME
python_3.5 hook.log

Now we can install some software into the environment.

(python_3.5)$ pip install django
Downloading/unpacking django
Downloading Django-1.1.1.tar.gz (5.6Mb): 5.6Mb downloaded
Running setup.py egg_info for package django
Installing collected packages: django
Running setup.py install for django
changing mode of build/scripts-2.6/django-admin.py from 644 to 755
changing mode of /Users/salayhin/Envs/env1/bin/django-admin.py to 755
Successfully installed django

We can see the new package with lssitepackages:

(python_3.5)$ lssitepackages
Django-1.1.1-py2.6.egg-info easy-install.pth
setuptools-0.6.10-py2.6.egg pip-0.6.3-py2.6.egg
django setuptools.pth

We can create multiple virtual environment if we want.

Switch between environments with workon:

(python_3.6)$ workon python_3.5
(python_3.5)$ echo $VIRTUAL_ENV
/Users/salayhin/Envs/env1
(python_3.5)$

To exit the virtualenv

$ deactivate