[Python] Use Virtualenv, venv to isolate environments

 Python   Virtualenv    venv  

▌Introduction

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We will learn how to use Virtualenv and venv(available in Python 3) for running isolated environments with different versions of packages.

▌Environment

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▋Windows 10

▋Git bash

▋Python 3.6.2

▌Virtualenv

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▋Install Virtualenv

$ python –m pip install virtualenv

▋Create virtual environment

$  winpty virtualenv {environment_name} [--no-site-packages] [--python=/c/Python25/python.exe]

[--no-site-packages]

Do not access to global site-packages. (Default)

[--system-site-packages]

The virtual environment will inherit packages from site-packages.

[--python=/c/Python25/python.exe]

Specify the Python interpreter to use in this virtual environment.

For example,

winpty virtualenv myProject --no-site-packages --python=/C/Users/JB/AppData/Local/Programs/Python/Python36-32/python.exe

▋Activate and deactivate

To activate the virtual environment in Windows,

$ source {environment_name}/Scripts/activate

Which will result in appending the environment name as the prefix of shell command.

To deactivate it,

$ deactivate

Furthermore, we can force pip to be used only in an active virtual environment by adding the following line to your ~/.bashrc file.

$ export PIP_REQUIRE_VIRTUALENV=true

 

▌venv

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venv is a package shipped with Python 3, no need to install it manually.

▋Create virtual environment

$ python -m venv {environment_name} [--system-site-packages]

For example,

python -m venv venv/MyProject

▋Activate and deactivate

▋Activate

$ source {environment_name}/Scripts/activate

▋Deactivate

$ deactivate

▌Reference

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▋venv — Creation of virtual environments

▋Virtualenv

▋What is the difference between venv, pyvenv, pyenv, virtualenv, virtualenvwrapper, pipenv, etc?