- Trending Categories
- Data Structure
- Operating System
- C Programming
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Python Virtual Environment
Developers often deal with python projects where they have to use module and packages which were not part of the python standard library and they need it for this particular application only. Consider a case, where you have installed the current version of python (let’s assume its python-3.6) but your project requires specific python version--2.7 for this particular application, so it's not just the new packages but requirement may come for a particular version of your already installed application. Then the requirements are in conflict and installing either version 2.7 or 3.6 will leave one application unable to run.
One solution to resolve these circumstances is to create a virtual environment for your project. Virutalenv is a kind of tool that allows us to create isolated python environments. Virtualenv creates a self-contained folder which contains all the required executables to use the packages that a Python project would require in its project.
Why we want it?
The main purpose of using virtualenv (virutal environment tool) is to resolve the issues of dependencies, versions (of python packages) and indirectly permissions.
Requirements for installing Virtual Environment
First thing first, you need to have the python installed in your machine (not necessarily the latest version) and pip package manager. However, if you are using python 3.4 version or higher, pip is included by default (comes as python standard library). In case you don’t have any one of them, it’s recommended to installing it first.
Creating Virtual Environments
Open your command prompt(type cmd in your run terminal). Now go to the directory path(location), where you want to install the virtual environment.
In case you are not using python 3.x, then you need to install the virtualenv tool with pip.
pip install virtualenv
In case virtualenv is already installed (either you are using python 3 version or you’re not aware of virtualenv installed already), then running above command will give you message something like,
>pip install virtualenv Requirement already satisfied: virtualenv in c:\python\python361\lib\site-packages (15.1.0)
Start by creating a new folder to work with
mkdir python-virtual-environments && cd python-virtual-environments
After running above command, you are inside the newly created folder. Now create a new virtual environment inside the directory (the directory you created above).
#For python 2.x version −
# For python 3.x version −
python -m venv myenv
Above script will create a new folder name myenv with a couple of directories and lots of files, with a directory structure similar to below -
├── Include │ ├── abstract.h │ ├── accu.h │ ├── asdl.h │ ├── ast.h │ ├── bitset.h ……… ├── Lib │ ├── __future__.py │ ├── __pycache__ │ ├── _bootlocale.py │ ├── _collections_abc.py │ ├── _dummy_thread.py │ ├── _weakrefset.py │ ├── abc.py │ ├── base64.py │ ├── bisect.py │ ├── codecs.py …… ├── pip-selfcheck.json ├── Scripts │ ├── activate │ ├── activate.bat │ ├── activate.ps1 │ ├── activate_this.py │ ├── deactivate.bat │ ├── easy_install.exe │ ├── easy_install-3.6.exe │ ├── pip.exe │ ├── pip3.6.exe │ ├── pip3.exe │ ├── python.exe │ ├── python36.dll │ ├── pythonw.exe │ └── wheel.exe
Include (directory): C headers that compile the python package
Scripts(directory): files that interact with the virtual environment
Lib(directory): Contains the python version copy and site-packages directory where each dependency is installed.
How to activate the virtual environment?
One of the interesting files is the activate scripts in the scripts directory. The activate scripts used the environment’s python executables and its site-package by default to set up your shell.
However, to use this virtual environment “myenv” packages or resources in isolation, you need to “activate” it first. To activate your virtual environment run the command as shown in the screenshot.
Once the virtual environment is active, we can install all the project related packages and other dependencies isolated from the outside world. For example, if we are working with a data science project, we can install all the required packages and their dependencies at once simply, by typing below command like below −
(myenv) C:\Users\rajesh\python-virtual-environments>pip install numpy scipy matplotlib ipython jupyter pandas
Once we are done with our project, we can come out of the virtual environment simply by deactivating it.
(myenv) C:\Users\rajesh\python-virtual-environments>deactivate C:\Users\rajesh\python-virtual-environments>
Now we are back in the windows command shell (like above).
- Creating Python Virtual Environment in Windows and Linux
- How to create a virtual environment in Python?
- Python Environment Variables
- CGI Environment Variables in Python
- What is the simplest way to make Matplotlib in OSX work in a virtual environment?
- Creation of virtual environments using Python
- What is PYTHONPATH environment variable in Python?
- Top-level script environment in Python (__main__)
- Add packages to Anaconda environment in Python
- Difference Between Virtual and Pure Virtual Function
- MySQL Environment Variables
- Virtual Private Server (VPS) vs. Virtual Private Network (VPN)
- Virtual - Circuit Network
- How to set python environment variable PYTHONPATH on Linux?
- How to set python environment variable PYTHONPATH on Mac?