1. Install python from https://www.python.org/downloads
2. Get pip from https://bootstrap.pypa.io/get-pip.py
3. Run python get-pip.py

Pipenv is a dependency manager for Python projects. While pip can install Python packages, Pipenv is recommended as it’s a higher-level tool that simplifies dependency management for common use cases.

$ pip install --user pipenv

$ cd myproject

$ pipenv install requests

$ pipenv run python main.py

$ pip install virtualenv

Test your installation

$ virtualenv --version

$ cd my_project_folder

$ virtualenv my_project

virtualenv my_project will create a folder in the current directory which will contain the Python executable files, and a copy of the pip library which you can use to install other packages. The name of the virtual environment (in this case, it was my_project) can be anything; omitting the name will place the files in the current directory instead.

This creates a copy of Python in whichever directory you ran the command in, placing it in a folder named my_project.

You can also use the Python interpreter of your choice (like python2.7).

$ virtualenv -p /usr/bin/python2.7 my_project

or change the interpreter globally with an env variable in ~/.bashrc:

$ export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python2.7

$ source my_project/bin/activate

$ deactivate

virtualenvwrapper provides a set of commands which makes working with virtual environments much more pleasant. It also places all your virtual environments in one place.

To install (make sure virtualenv is already installed):

$ pip install virtualenvwrapper

$ export WORKON_HOME=~/Envs

Full instauctions: https://virtualenvwrapper.readthedocs.io/en/latest/install.html

$ export WORKON_HOME=~/Envs

$ mkdir -p $WORKON_HOME

$ source /usr/local/bin/virtualenvwrapper.sh

$ mkvirtualenv my_project

mkvirtualenv my_project --python=python3

mkvirtualenv my_project --python=python2

$ pip install virtualenvwrapper-win

In Windows, the default path for WORKON_HOME is %USERPROFILE%Envs

1. Create a virtual environment

Windows:

$ mkvirtualenv my_project

Linux:

$ mkproject my_project

This creates the my_project folder inside ~/Envs.

2. Work on a virtual environment:

$ workon my_project

virtualenvwrapper provides tab-completion on environment names. It really helps when you have a lot of environments and have trouble remembering their names.

workon also deactivates whatever environment you are currently in, so you can quickly switch between environments.

3. Deactivating is still the same:

$ deactivate

4. To delete:

$ rmvirtualenv venv

python3 -m venv envname

only windows:

cd name

setproject dir .

lsvirtualenv

workon

       List all of the environments.

cdvirtualenv

       Navigate into the directory of the currently activated virtual environment, so you can browse its site-packages, for example.

cdsitepackages

       Like the above, but directly into site-packages directory.

lssitepackages

       Shows contents of site-packages directory.

When you cd into a directory containing a .env, autoenv automagically activates the environment.

Install it on Mac OS X using brew:

$ brew install autoenv

And on Linux:

$ git clone git://github.com/kennethreitz/autoenv.git ~/.autoenv

$ echo 'source ~/.autoenv/activate.sh' >> ~/.bashrc

pip freeze > requirements.txt: save dependencies
pip install -r requirements.txt: install requirements

Links:

http://virtualenvwrapper.readthedocs.io/en/latest
http://docs.python-guide.org/en/latest/dev/virtualenvs
http://virtualenvwrapper.readthedocs.io/en/latest/install.html#basic-installation  
http://sourabhbajaj.com/mac-setup/Python/virtualenv.html