Embrace Python

Introduction level talk about Python held at ISDC Romania. Covers the history of Python, the "pythonic" philosophy, standard lib, web programming and some further learning resources.

Transcript

1. http://bash.org/?400459 <Sonium> someone speak python here? <lucky> HHHHHSSSSSHSSS <lucky> SSSSS <Sonium> the programming language
2. Embrace Python http://0chris.com/embrace-python
3. Who am I ? • Christian Stefanescu • http://0chris.com • chris@0chris.com • twitter.com/0_chris • github.com/stchris • Software Developer at AcmePacket Berlin (http://www.acmepacket.com) • Team Lead – Infrastructure Team • Using Python for more than 5 years
4. What we do with Python • Products: Palladion, PonD, FDP • Python everywhere! • Build system • Integration testing • Installer • Daemons • Clean-up and maintenance scripts • Internal web apps, IRC bot • Integrating Mercurial with other tools
5. Scope of this talk • Python overview • What is it? • How can it help me? • How can it help my company? • Why would I use it? • Where can I use Python?
6. History & General Info
7. History • Late 1980's • Guido BDFL • PSF
8. Python is ... • … a strongly typed, dynamically typed language • … an interpreted language (with a byte- compiler) • … available for Linux/Unix, Mac OS X, Windows, JVM, CLR • … multi-paradigm: OO, imperative, functional
9. Duck typing • „It walks like a duck and it quacks like a duck, so it must be a duck“ • Set of methods and attributes (and not inheritance) determines the context
10. „Batteries included“ • Standard library is huge: base64, gzip, bzip, zip, tar, zlib, sockets, smtp/imap, url, http server, cookie, argument parser, confg fle parser, logging, serialization, csv fles, json, event scheduling, regex, struct, collections, path, tempfle, sqlite3, memory-mapped fles, in- memory fle-like objects, thread-like process lib, signals, subprocess, async i/o, xml handling, unittest, doctest, pdb (debugger), inspect, trace • REPL, IDLE
11. Significant whitespace • No braces - Indentation matters
12. PEPs • Python Enhancement Proposal • Design documents for new features • Include rationale, explanation, implementation suggestions • Openly discussed on python-dev ML • Approved by BDFL
13. Style Guide for Python (PEP-8) • Code is read more often than written • Covers: • Tabs vs. Spaces • Whitespace in expressions, statements • Comments • Naming conventions
14. The Zen of Python (PEP-20) • Beautiful is better than ugly. • Explicit is better than implicit. • Simple is better than complex. • Complex is better than complicated. • Flat is better than nested. • Sparse is better than dense. • Readability counts. • Special cases aren't special enough to break the rules. • Although practicality beats purity.
15. The Zen of Python (PEP-20) • Errors should never pass silently. • Unless explicitly silenced. • In the face of ambiguity, refuse the temptation to guess. • There should be one-- and preferably only one --obvious way to do it. • Although that way may not be obvious at frst unless you're Dutch. • Now is better than never. • Although never is often better than *right* now. • If the implementation is hard to explain, it's a bad idea. • If the implementation is easy to explain, it may be a good idea. • Namespaces are one honking great idea -- let's do more of those!
16. Modules & Packages
17. Data types • int, float • str, unicode • list, tuple • dict • boolean types: True, False
18. Functions • Default values instead of overloading • Lambdas • Can be nested • Decorators
19. Iterable types Sequence types Iterator
20. Generators • Function that behaves like an iterable
21. Classes
22. Public / Protected / Private • „We are all consenting adults“ • Object.public • Object._protected • Object.__private
23. Context Managers
24. Exceptions
25. Packaging, Distribution
26. • „I buy my eggs at the cheese shop“ • .egg • PyPi – the cheese shop • Pip • Setup.py
27. State of packaging • distutils - built-in • setuptools – 3rd party • distribute – successor to setuptools • packaging (distutils2) – not in 3.3
28. Virtualenv • PYTHONPATH • PyPi • pip
29. Web Development with Python
30. WSGI (PEP-333, PEP-3333)
31. Django • „The web framework for perfectionists with deadlines“ • opinionated • pluggable apps • Admin interface • ORM • templating • caching • i18n
32. Flask • microframework • ~800 lines of code, ~1500 lines of tests • BYO ORM, templating, caching, … • suitable for heavy lifting
33. Requests (HTTP for Humans) • stdlib support for http is broken • sane API • SSL • Cookies • Basic/digest/OAuth
34. Twisted • Async programming framework • Network oriented • Protocol interfaces (clients, factories) • Plugin system
35. Present and Future
36. Promising future developments • pypy • Python3 • Android • SL4A • python-android • Kivy (http://kivy.org)
37. Recommended resources
38. Learn • http://docs.python.org/tutorial/ • http://reddit.com/r/python (right sidebar) • http://www.doughellmann.com/PyMOTW/ • http://www.python-guide.org • Hitchhiker's guide to packaging: http://guide.python-distribute.org/
39. Use • http://www.trypython.org/ • Type python in the command line • ipython, bpython • http://docs.python.org - API/module reference
40. Stay in touch • Reddit.com/r/python • Planet.python.org • https://groups.google.com/group/python- romania • http://python.org/community/ • http://twitter.com/getpy • http://pythonweekly.com
41. Summary
42. To me, Python is ... • … „executable pseudocode“ • … a swiss-army knife • … future-proof • … elegant • … compact
43. Questions ?
44. Thanks ! http://0chris.com/embrace-python