Python Installation and Setup

# Option 1: Microsoft Store (easiest)
# Search "Python 3.12" in Microsoft Store and install

# Option 2: Official installer from python.org
# Download python-3.12.x-amd64.exe
# IMPORTANT: check "Add Python to PATH" during install

# Option 3: winget (package manager)
winget install Python.Python.3.12

# Option 4: Chocolatey
choco install python

# Option 1: Homebrew (recommended)
brew install python@3.12

# Option 2: Official installer
# Download from python.org/downloads/mac-osx/
# Installs to /Library/Frameworks/Python.framework/

# Option 3: pyenv (best for managing multiple versions)
brew install pyenv
pyenv install 3.12.3
pyenv global 3.12.3   # set as default

# Ubuntu / Debian
sudo apt update
sudo apt install python3.12 python3.12-venv python3-pip

# Fedora / RHEL
sudo dnf install python3.12

# From source (any Linux - gives latest version)
sudo apt install build-essential libssl-dev zlib1g-dev
wget https://www.python.org/ftp/python/3.12.3/Python-3.12.3.tgz
tar xf Python-3.12.3.tgz && cd Python-3.12.3
./configure --enable-optimizations
make -j$(nproc) && sudo make altinstall

# Check Python version
python3 --version      # Python 3.12.3
python --version       # may be Python 2.x on some systems
py --version           # Windows py launcher

# Check pip
python3 -m pip --version   # pip 24.0 from ...

# Check where Python is installed
which python3          # /usr/local/bin/python3 (macOS/Linux)
where python           # C:\Python312\python.exe (Windows)

# Quick test in terminal
python3 -c "print('Python is working!')"

# Create a virtual environment in a folder called .venv
python3 -m venv .venv

# Activate it
source .venv/bin/activate      # macOS / Linux
.venv\Scripts\activate         # Windows PowerShell
.venv\Scripts\activate.bat     # Windows CMD

# Prompt changes to show the active venv:
# (.venv) alice@machine:~/project$

# Now install packages - they go into .venv only
pip install requests pandas

# See what is installed
pip list
pip freeze > requirements.txt   # save exact versions

# Install from a requirements file
pip install -r requirements.txt

# Deactivate when done
deactivate

# Install a package
pip install requests
pip install requests==2.31.0     # specific version
pip install "requests>=2.28"     # minimum version

# Install multiple packages
pip install fastapi uvicorn pydantic

# Upgrade a package
pip install --upgrade requests

# Uninstall
pip uninstall requests

# Search PyPI (or visit pypi.org)
pip search requests    # deprecated; use pypi.org instead

# Show package info and location
pip show requests

# List outdated packages
pip list --outdated

# Use python -m pip to ensure the right Python
python3 -m pip install requests   # safer than bare 'pip'

# Install VS Code extensions (from terminal)
code --install-extension ms-python.python          # Python extension (official)
code --install-extension ms-python.pylance         # Type checking + autocomplete
code --install-extension ms-python.black-formatter # Auto-formatting

# Or install from VS Code Extensions panel (Ctrl+Shift+X)
# Search: "Python" by Microsoft

# Select interpreter in VS Code:
# Ctrl+Shift+P -> "Python: Select Interpreter"
# Choose your .venv Python (e.g., ./.venv/bin/python)

# settings.json additions for Python
# "python.defaultInterpreterPath": "${workspaceFolder}/.venv/bin/python"
# "[python]": { "editor.formatOnSave": true, "editor.defaultFormatter": "ms-python.black-formatter" }

$ python3
Python 3.12.3 (main, Apr  9 2024, 08:09:14)
>>> 2 + 2
4
>>> name = "Alice"
>>> f"Hello, {name}!"
'Hello, Alice!'

>>> # Explore an object's methods
>>> dir([])
['append', 'clear', 'copy', 'count', ...]

>>> # Get help on any object
>>> help(str.split)

>>> # Multi-line input - use ... continuation
>>> def add(a, b):
...     return a + b
...
>>> add(3, 4)
7

>>> exit()   # or Ctrl+D (macOS/Linux), Ctrl+Z Enter (Windows)