#28 The meaning of _ in Python
Python Bytes - Podcast tekijän mukaan Michael Kennedy and Brian Okken - Maanantaisin
Kategoriat:
Brian #1: pep8.org : PEP 8 — the Style Guide for Python Code
- "This stylized presentation of the well-established PEP 8 was created by Kenneth Reitz (for humans)."
- From PEP 8: "This document gives coding conventions for the Python code comprising the standard library in the main Python distribution."
- PEP8 is not only used for the standard library. Many if not most open source Python packages adhere to at least most of the PEP8 recommendations
- testing plugins can help you make sure your code meets the guidelines (for good or bad).
- The pep8.org presentation is easy to read, with a left side clickable table of contents.
- Nice color coded examples. Green for good, Red for bad.
- links to specific items make it easy to share with others something specific.
- Good advice, but don't be a pep8-bully.
Michael #2: Tokio: Asyncio event loop written in Rust language
- Asyncio event loop written in Rust language
- It is still in alpha stage.
- It provides most of asyncio event loop apis, except udp.
- TCP api is more or less stable
- Aiohttp tests pass with tokio loop (~1800 tests)
- Mostly interesting as an example of Rust + Python
- Project is still in early stage of development
Brian #3: Python Boilerplate
- Interactive online tool for creating script and small project boilerplate code.
- Just starting, with "how to help" link.
- Select
- Python 2 or 3
- executable script or not
- argparse
- logging
- .gitignore
- Flask
- unittest or pytest
- tox
- fills in main.py, plus other files like test_sample.py, requirements.txt, tox.ini, etc.
Michael #4: Instagram switching to Python 3 on one branch
- Ancient Django but still productive
- Ran out of 32-bit user IDs before they ran out of Django power.
- Added sharing support to Django Orem
- Turned off GC for perf
- Upgraded entirely to 3.6 in a few months
- Why?
- Type hints
- Scaling server perf
- asyncio
- Python 3 is where the future community work is happening
- Strategies
- No user impact
- Still shipping
- Testing process was interesting
- This is a concrete roadmap for every large company
Brian #5: The Meaning of Underscores in Python
- single and double underscore meanings
- dunder is "double underscore"
- Single Leading Underscore:
_var
- Single Leading Underscore:
- method or variable for internal use
- convention only
- doesn't apply to
collection.namedtuple
- Single Trailing Underscore:
var_
- Single Trailing Underscore:
- used to avoid name collision with keywords
- Double Leading Underscore:
__var
- Double Leading Underscore:
- internal use by a single class level.
- Python will name mangle this so that subclasses don't have to avoid parent class double leading underscore names
- Double Leading and Trailing Underscore:
__var__
- Double Leading and Trailing Underscore:
- no name mangling
- special names. dunder methods
__call__
and__init__
, etc.- Single Underscore:
_
- Single Underscore:
- in code : temp variable, don't care variable
- won't get a warning if you don't reference it again
- in REPL: last value
Michael #6: The future is looking bright for Python
- Stack Overflow recently released a cool new tool called Trends (previously covered)
- Check out the Most Popular Languages trend chart
- Python has, by a very large margin, the greatest positive slope (future?)
- And Py3 vs Py2