#58 Better cache decorators and another take on type hints

Sponsored by DigitalOcean: http://do.co/python

Brian #1: Instagram open sources MonkeyType

• Carl Meyer, an engineer on Instagram’s infrastructure team.
• (Note: we talked about Dropbox’s pyannotate in episode 54. pyannotate is not on Python3 yet and generates comment style annotations that are Py2 compatible)
• MonkeyType is Instagram’s tool for automatically adding type annotations to your Python 3 code via runtime tracing of types seen.
• Requires Python 3.6+
• Generates only Python 3 style type annotations (no type comments)

Michael #2: cachetools

• Extensible memoizing collections and decorators
• Think variants of Python 3 Standard Library @lru_cache function decorator
• Caching types:
  • cachetools.Cache Mutable mapping to serve as a simple cache or cache base class.
  • cachetools.LFUCache Least Frequently Used (LFU) cache implementation
  • cachetools.LRUCache Least Recently Used (LRU) cache implementation
  • cachetools.TTLCache LRU Cache implementation with per-item time-to-live (TTL) value.
  • And more
• Memoizing decorators
  • cachetools.cached Decorator to wrap a function with a memoizing callable that saves results in a cache.
  • Note that cache need not be an instance of the cache implementations provided by the cachetools module. cached() will work with any mutable mapping type, including plain dict and weakref.WeakValueDictionary.
  • Can pass key function for hash insertions and lock object for thread safety.

Brian #3: Going Fast with SQLite and Python

• Charles Leifer
• Many projects start with SQLite, as it’s distributed with Python as sqlite3.
• This article discusses some ways to achieve better performance from SQLite and shares some tricks.
  • transactions, concurrency, and autocommit
  • user-defined functions
  • using pragmas
  • compilation flags

Michael #4: The graphing calculator that makes learning math easier.

• A full graphing calculator
• Programmable in Python
• Exam approved: Take the SAT and the ACT.
• Free browser emulator

Brian #5: Installing Python Packages from a Jupyter Notebook

• Jake VanderPlas
• using conda import sys !conda install --yes --prefix {sys.prefix} numpy
• using pip import sys {sys.executable} -m pip install numpy
• plus a discussion of why this is weird in Jupyter

Michael #6: Videos from PyConDE 2017 are online

• via Miroslav Šedivý @eumiro
• Lots of interesting talk titles
• Almost all in English