py library

1.11.0 · active · verified Sat Mar 28

The 'py' library provides a collection of powerful, low-level utilities primarily focused on filesystem path manipulation, INI parsing, I/O, Python code introspection, and logging. Maintained by the pytest-dev team, it often serves as a foundational component for other testing and development tools. It is currently at version 1.11.0 and has a stable release cadence.

Warnings

gotcha For new projects or general file system path manipulation, Python's built-in `pathlib` module (introduced in Python 3.4) is often the more idiomatic and recommended choice over `py.path`. `pathlib` provides a fully object-oriented interface for paths and is part of the standard library.
Fix: Consider using `from pathlib import Path` and its methods (`Path.cwd()`, `Path.joinpath()`, `Path.read_text()`, etc.) for modern Python development. `py.path` remains useful for compatibility with projects built around it (e.g., `pytest`) or for its specific utility functions.
gotcha The `py.log` module provides basic logging facilities. However, for robust application logging, structured logging, or integration with existing logging ecosystems, Python's standard `logging` module is generally more powerful and flexible, offering advanced features like handlers, formatters, and hierarchical loggers.
Fix: Evaluate whether Python's standard `logging` module meets your requirements for application-wide logging before opting for `py.log` for general use cases.
gotcha The `py.code` module offers powerful introspection and manipulation of Python code objects, often utilized by testing frameworks like `pytest`. Directly relying on `py.code` for general-purpose introspection or metaprogramming in application code might lead to less standard or harder-to-maintain solutions. Python's `inspect` module or `ast` module typically provide more standard APIs for these tasks.
Fix: For common code introspection needs, explore Python's standard `inspect` module. For code modification or static analysis, consider the `ast` module.

Install

pip install py Install stable version

Imports

path
```
import py.path; p = py.path.local('.')
```
Accessing the path utilities.

code

import py.code; c = py.code.Source('print("hello")')

Accessing code introspection utilities.

io
```
import py.io; cap = py.io.StdCapture()
```
Accessing I/O capturing utilities.

log

import py.log; py.log.setconsumer(my_consumer)

Accessing logging utilities.

Quickstart

This quickstart demonstrates basic file system operations using `py.path.local`, including creating a directory, writing to a file, reading from it, and cleaning up. This highlights the object-oriented approach to path manipulation provided by the `py` library.

import py
import os

# Create a temporary local path object
temppath = py.path.local('my_temp_dir')
temppath.ensure(dir=True) # Ensure it's a directory

# Join paths and write content
filepath = temppath.join('hello.txt')
filepath.write('Hello, py world!')

# Read content
print(filepath.read())

# Cleanup
filepath.remove()
temppath.remove()

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