virtualenvironment.md

What is a virtual environment?

Which tools do I use for a virtual environment?

Pipenv and Virtualenv

pip install pipenv pipenv install Pipfile

How do I set up a virtual environment?

In Windows,you can create a virtual environment with the following: virtualenv venv --python=<insert_your_python_version_here> where <insert_your_python_version_here> was in my case C:\Python\Python368\python.exe

In Linux, you can create a virtual environment with virtualenv venv --python=/usr/bin/python3.

Additional notes

Installing Python 3.7 and using pyenv (Linux)

Suppose you want to work with a specific version of Python for a project. What you can do is to set a .python-version file and then execute the main.py file with that particular version of python.

Based on the post from stackoverflow you need to execute the following commands to get up and running Python 3.7.0. (Linux Mint)

sudo apt-get update

sudo apt-get upgrade

sudo apt-get dist-upgrade

sudo apt-get install build-essential python-dev python-setuptools python-pip python-smbus

sudo apt-get install libncursesw5-dev libgdbm-dev libc6-dev

sudo apt-get install zlib1g-dev libsqlite3-dev tk-dev

sudo apt-get install libssl-dev openssl

sudo apt-get install libffi-dev

./configure

make

sudo make altinstall

Installing pyenv

curl -L https://raw.githubusercontent.com/yyuu/pyenv-installer/master/bin/pyenv-installer | bash

Testing pyenv

pyenv install 3.7.0 # install a new version in Linux

pyenv versions # see the current versions

Working with pyenv

vi main.py # type in this file a hello world program

pyenv local 3.7.0 # set the local python version to be 3.7.0

pyenv exec python main.py # this will execute the python file with the 3.7.0 version

Setting up a virtual environment with pyenv

You can create a virtual environment with a specific version of Python by first setting up the Python version you want and then using that version to create your virtual environment, that is,

mkdir appPython37 # create a new folder for the app that will work with Python 3.7

pyenv local 3.7.0 # set the local version to 3.7.0

pyenv exec python -m venv env # create the virtual environment with Python 3.7.0

With the commands from above you can have different virtual environments in various Python versions.

virtualenvwrapper

export PATH="/home/alexbr/.pyenv/bin:$PATH" eval "$(pyenv init -)" eval "$(pyenv virtualenv-init -)"

Setting up a virtual environment in Windows

pip install virtualenv # install virtualenv in Windows

virtualenv venv --python=C:\Python368\python.exe # set up the virtual environment version

./activate # You need to access to the venv folder and then Scripts. In case you are not allowed to run scripts due to the execution of scripts that is disabled then run the following command as admin in Powershell.

set-executionpolicy remotesigned

References:

https://stackoverflow.com/questions/27022373/python3-importerror-no-module-named-ctypes-when-using-value-from-module-mul

https://realpython.com/python-virtual-environments-a-primer/#managing-virtual-environments-with-virtualenvwrapper

https://superuser.com/questions/106360/how-to-enable-execution-of-powershell-scripts