Virtual Environment

A virtual environment (venv) is an isolated Python workspace for a project.

Q: Why need virtual environment

• Avoid dependency conflicts between projects
• Keep system Python clean
• Make installs reproducible via requirements.txt

Environment Setup

Prerequisites

• Python 3.10+ (recommended)
• pip available (comes with Python)

macOS / Linux

1) Create virtual environment

cd /project
python3 -m venv .venv

2) Activate the environment (macOS / Linux)

source .venv/bin/activate

After successfully activating the virtual environment, your prompt will look like:
(.venv) alanwang@...

3) Upgrade pip (recommended)

python -m pip install --upgrade pip

4) Install dependencies

# Install dependencies from requirements.txt
pip install -r requirements.txt

Install a single package

# Install dependencies
pip install <package-name>

Export dependencies

pip freeze > requirements.txt

5) Deactivate Virtual Environment

After Activate successfully source .venv/bin/activate

deactivate

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Linked to: env Guide