Virtual Environments

Virtual Environments

A virtual environment gives each project its own isolated set of packages. Projects can use different versions without fighting.

Why isolate?

Two projects may need different versions of the same library. Without isolation, installing one breaks the other. A venv fixes that.

Create a virtual environment

python -m venv myenv

This makes a folder named myenv with its own Python and pip.

Activate it

On Windows:

myenv\Scripts\activate

On macOS/Linux:

source myenv/bin/activate

Install into the environment

Once active, use pip as usual. The packages go into the environment, not your system:

pip install requests

Deactivate

deactivate

Freeze your dependencies

Share what your project needs:

pip freeze > requirements.txt

Others install it all at once:

pip install -r requirements.txt

TL;DR

• python -m venv name creates an isolated environment.
• Activate it before installing packages.
• deactivate leaves it.
• requirements.txt shares dependencies.