# Mastering Python Virtual Environments: Setup and Best Practices
URL: https://madhudadi.in/blog/posts/python-virtual-environments-setup-and-usage-guide
Published: 2026-06-10
Tags: python, setup
Read time: 44 min
Difficulty: beginner
> Learn Python virtual environments with venv: create .venv, activate it, install packages, freeze requirements, recreate environments, and avoid dependency conflicts.# Python Virtual Environments: venv, Activation, pip, and requirements.txt

## Quick Answer

A virtual environment is a private Python environment for one project.

Use one `.venv` per project.

Windows:

```powershell
py -m venv .venv
.\.venv\Scripts\Activate.ps1
```

macOS:

```bash
python3 -m venv .venv
source .venv/bin/activate
```

Last verified: June 9, 2026.

## Official Links

- Python `venv` docs: https://docs.python.org/3/library/venv.html
- Python tutorial on virtual environments: https://docs.python.org/3/tutorial/venv.html
- Python packaging guide: https://packaging.python.org/en/latest/guides/installing-using-pip-and-virtual-environments/
- pip docs: https://pip.pypa.io/en/stable/

## What You Will Learn

By the end, you should be able to:

- explain why virtual environments matter
- create a `.venv` folder
- activate and deactivate environments on Windows and macOS
- install packages inside the environment
- create `requirements.txt`
- recreate an environment from scratch
- know what should and should not go into Git

## 1. Why Virtual Environments Exist

Different projects need different packages.

Example:

```text
project-a needs pandas 2.3
project-b needs pandas 2.0
```

If both projects use one global Python, packages can conflict.

With virtual environments:

```text
project-a/.venv has project-a packages
project-b/.venv has project-b packages
```

The environment is disposable. Your code is important. `.venv` can always be deleted and recreated.

## 2. Create A Project Folder

Windows PowerShell:

```powershell
mkdir python-venv-practice
cd python-venv-practice
```

macOS:

```bash
mkdir python-venv-practice
cd python-venv-practice
```

## 3. Create The Virtual Environment

Windows:

```powershell
py -m venv .venv
```

macOS:

```bash
python3 -m venv .venv
```

Linux:

```bash
python3 -m venv .venv
```

`.venv` is the common folder name. Do not put your source code inside `.venv`.

## 4. Activate The Virtual Environment

| Platform | Shell | Activation command |
| --- | --- | --- |
| Windows | PowerShell | `.\.venv\Scripts\Activate.ps1` |
| Windows | Command Prompt | `.venv\Scripts\activate.bat` |
| macOS | zsh/bash | `source .venv/bin/activate` |
| Linux | bash/zsh | `source .venv/bin/activate` |
| macOS/Linux | fish | `source .venv/bin/activate.fish` |

After activation, your prompt often begins with:

```text
(.venv)
```

## 5. Verify The Environment

After activation, run:

```bash
python -c "import sys; print(sys.executable)"
python -m pip --version
```

Expected result:

- the Python path includes `.venv`
- pip also points inside `.venv`

On Windows, the path may include:

```text
.venv\Scripts\python.exe
```

On macOS, the path may include:

```text
.venv/bin/python
```

## 6. Install Packages Inside The Environment

After activation:

```bash
python -m pip install pandas matplotlib
```

Test:

```bash
python -c "import pandas as pd; print(pd.__version__)"
```

The packages are installed into `.venv`, not into your global Python.

## 7. Deactivate

To leave the environment:

```bash
deactivate
```

This removes `.venv` from the active terminal PATH.

## 8. Create requirements.txt

After installing packages:

```bash
python -m pip freeze > requirements.txt
```

Example:

```text
pandas==2.3.0
matplotlib==3.10.0
```

Commit `requirements.txt` to Git.

## 9. Recreate The Environment

If `.venv` is deleted or someone else downloads your project, recreate it.

Windows:

```powershell
py -m venv .venv
.\.venv\Scripts\Activate.ps1
python -m pip install -r requirements.txt
```

macOS:

```bash
python3 -m venv .venv
source .venv/bin/activate
python -m pip install -r requirements.txt
```

## 10. What Goes Into Git?

Commit:

```text
your_code.py
requirements.txt
README.md
data/sample.csv
```

Do not commit:

```text
.venv/
__pycache__/
.env
```

Beginner `.gitignore`:

```gitignore
.venv/
__pycache__/
*.pyc
.env
```

## 11. PowerShell Activation Error

If PowerShell says scripts are disabled, run:

```powershell
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
```

Then close and reopen PowerShell.

Activate again:

```powershell
.\.venv\Scripts\Activate.ps1
```

This changes policy only for your current Windows user.

## 12. macOS PATH Or Activation Problems

If activation fails, confirm the folder exists:

```bash
ls .venv/bin
```

If `python3 -m venv .venv` fails, check Python:

```bash
python3 --version
which python3
```

If the terminal cannot find newly installed tools, restart Terminal or reload zsh config:

```bash
source ~/.zshrc
```

## 13. Should You Use `venv` Or `uv`?

Use `venv` when:

- you are learning Python fundamentals
- a course asks for plain Python tooling
- you want to understand environments clearly

Use `uv` when:

- you want faster project setup
- you want lockfiles
- you want one tool for Python versions, environments, and packages

`uv` is covered in the next post.

## Practice Task

Create an environment, install pandas, and run this file:

```python
import pandas as pd

scores = pd.DataFrame({
    "name": ["Asha", "Ben", "Chen"],
    "score": [88, 91, 79],
})

print(scores)
print("Average:", scores["score"].mean())
```

If it runs, your environment works.

## FAQ

### Should I create `.venv` inside every project?

Yes. It keeps project dependencies separate and easy to recreate.

### Should I commit `.venv` to Git?

No. Commit `requirements.txt` or `pyproject.toml`, then recreate `.venv` later.

### Do I need to activate the environment every time?

For terminal work, yes. IDEs can also select the `.venv` interpreter directly.

### Can I move a `.venv` folder to another computer?

Do not rely on that. Recreate it from `requirements.txt`.

## Final Checklist

Windows:

```powershell
py -m venv .venv
.\.venv\Scripts\Activate.ps1
python -c "import sys; print(sys.executable)"
python -m pip install requests
python -m pip freeze > requirements.txt
deactivate
```

macOS:

```bash
python3 -m venv .venv
source .venv/bin/activate
python -c "import sys; print(sys.executable)"
python -m pip install requests
python -m pip freeze > requirements.txt
deactivate
```

If the Python path includes `.venv`, the setup is correct.