uv-python-versions

# UV Python Version Management

Quick reference for installing and managing Python interpreter versions with UV.

## When This Skill Applies

- Installing specific Python versions
- Switching between multiple Python versions
- Pinning Python versions for projects
- Managing CPython and PyPy interpreters
- Finding and listing installed Python versions

## Quick Reference

### Installing Python Versions

```bash
# Install latest Python
uv python install

# Install specific version
uv python install 3.11
uv python install 3.12
uv python install 3.10 3.11 3.12

# Install exact version
uv python install 3.11.5
uv python install cpython@3.11.5

# Install PyPy
uv python install pypy@3.9
uv python install pypy@3.10
```

### Listing Python Versions

```bash
# List all available versions
uv python list

# List only installed versions
uv python list --only-installed

# List with verbose details
uv python list --verbose
```

### Pinning Python Versions

```bash
# Pin version for current project
uv python pin 3.11
uv python pin 3.12.1

# Pin PyPy
uv python pin pypy@3.9

# Pin with version file
# Creates/updates .python-version
```

### Finding Python Interpreters

```bash
# Find any Python installation
uv python find

# Find specific version
uv python find 3.11
uv python find 3.12

# Find PyPy
uv python find pypy
uv python find pypy@3.9
```

### Using Specific Python Versions

```bash
# In project commands
uv run --python 3.11 script.py
uv run --python 3.12 pytest

# Creating virtual environments
uv venv --python 3.11
uv venv --python 3.10 .venv-py310

# Initializing projects
uv init --python 3.12 my-project
```

## Python Version Sources

UV searches for Python in this order:
1. **UV-managed** - Installed via `uv python install`
2. **.python-version** - Pin file in project directory
3. **pyproject.toml** - `requires-python` field
4. **System Python** - Existing system installations
5. **Environment** - `$PATH` and standard locations

## Version Pinning

### .python-version File