07-virtualenv.md

Python Virtual Environment (virtualenv)

Video Link: https://youtu.be/CHpQF1rdUMY

Virtual environments allow us to manage separate and isolated Python environments for each of our Python projects.

In this video, we learned to create and manage our own virtual environments for different Python projects using a tool named virtualenv.

Programs in the Video

• Create Virtual Environments
• Activate Virtual Environments
• Deactivate Virtual Environments

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Create Virtual Environments

In order to create a virtual environment, we can use the virtualenv module.

To install virtualenv:

pip install virtualenv

Let's now look at how we can create virtual environments.

Let's first create a directory in our current working space:

mkdir project1
cd project1

By default, we are using the global Python environment.

which python

Output

/usr/bin/python

If we do pip list, we can see the list of currently installed packages and libraries in the global Python installation.

Now let's create an isolated Python environment.

python -m virtualenv venv

We can see that a venv directory gets created in the current workspace. This directory contains minimal Python setup and executables for our Python project.

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Activate Virtual Environments

Now that we have created a virtual environment, let's activate it:

On Windows

.\venv\Scripts\activate

On Unix/Mac

source venv/bin/activate

Now, which python shows us that instead of the global Python, we are using Python which is inside our virtual environment.

Let me now install a specific version of the requests library in this virtual environment.

pip install requests==1.1.0

This version of requests is now available only for this virtual environment. It will not have any effect on our global Python setup.

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Deactivate Virtual Environments

In order to deactivate a virtual environment, we can simply use the deactivate command on our terminal.

deactivate

Using a virtual environment will prove very useful once you start working on a number of projects with different requirements.

You can then put all the additional requirements in a requirements file. This requirement file can then be used to set up the same type of virtual environment on any machine using:

pip install -r requirements.txt

If you want to remove a virtual environment, you can just delete the folder containing the virtual environment.