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.

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