Python is a dynamic programming language that is designed for readability and simplicity. It can be used for web applications, data analysis, GUIs, games, and more. Some key features of Python include being highly readable, using intuitive and clear naming conventions, being interactive and forgiving, treating everything as an object, and using generators and list/dict/set comprehensions which allow data to be projected in a functional style.

1.
Utan stödhjul och
motorsåg

2. Vad är Python?
● Ett dynamiskt typat språk
● Designat för enkelhet och tydlighet

3. It is the only language co-designed for the
most advanced and the complete novice.
[David Goodger]

4. Plattformar
● Python = CPython
● Jython (JVM)
● IronPython (.NET, Mono)
● PyPy (Python in Python)

5. Användningsområden
admin, byggen och driftsättning
webbapps, webbtjänster/+klienter
verktygsklister & GUIn (vanligt på linux)
dataskyffling/-konvertering/-analys

6. Scripta verktyg
Grafik (Gimp, Inkscape, Blender, ...),
LibreOffice, ...
Spel (Battlefield 2+, Civ IV, EVE-Online, ...)
DVCS: Mercurial, Bazaar...

7. Användare

11. .. Sun, Microsoft, Canonical, O'Reilly, Lucasfilm,
Nasa, Sourceforge, ...

12. Årets språk enligt Tiobe
Bästa tillväxten
2007
2010

13. Moget
Utveckling & drift: doctest, nosetests, distribute,
pip, virtualenv, ...
Paket för allt: data, sysadmin, webb, grafik,
matematik, parallellism...

14. Design

15. Vad är viktigt?
Läsbarhet!
Namngivning!

16. Programming The
Way Guido Indented It

17. def to_roman(num):
assert num > 0 and num < 4000
result = []
for d, r in NUMERALS:
while num >= d:
result.append(r)
num -= d
return ''.join(result)

18. "In soviet russia, braces scope you"
from __future__ import braces
...
SyntaxError: not a chance

19. Effektivt
tokens = ['a', 'b', 'c', 'B', 'dd', 'C', 'DD']
similar = {}
for token in tokens:
key = token.lower()
similar.setdefault(key, []).append(token)

20. Lättanvänt
for key, tokens in similar.items():
if len(tokens) > 1:
print("Similar (like %s):" % key)
for token in tokens:
print(token)

21. Generella behållare
● list() == []
● dict() == {}
● tuple() == ()
● set()

22. Python är interaktivt
$ python
Python 2.7.1 [...]
Type "help", "copyright", "credits" or "license" for
more information.
>>>

23. >>> def add(a, b=1):
... return a + b
...
>>> add(1)
2
>>> add(1, 2)
3
>>> add(2, b=3)
5
>>> add(b=3, a=2)
5

24. Mekanik

25. """
Usage:
>>> usr = Path('/usr')
>>> bin = usr.segment('local').segment('bin')
>>> str(bin)
'/usr/local/bin'
"""
class Path:
def __init__(self, base):
self.base = base
def segment(self, name):
return Path(self.base + '/' + name)
def __str__(self):
return self.base

26. __protokoll__
Betyder används under ytan

27. Tydliga sammanhang
Börjar bukta när en dålig idé växer
● state är explicit (self)

28. """
Usage:
>>> usr = Path('/usr')
>>> bin = usr.segment('local').segment('bin')
>>> str(bin)
'/usr/local/bin'
"""
class Path(str):
def segment(self, name):
return Path(self + '/' + name)

29. Allt är objekt
● primitiver
● collections
● funktioner, klasser
● moduler, paket

30. Ingen motorsåg..

31. """Usage:
Closures
>>> mkpasswd = salter("@secret#salt")
>>> mkpasswd("qwerty")
'4ef6056fb6f424f2e848705fd5e40602'
"""
from hashlib import md5
def salter(salt):
def salted_encrypt(value):
return md5(salt + value).hexdigest()
return salted_encrypt

32. Funktionell @dekoration
from django.views.decorators.cache import cache_page
@cache_page(15 * 60)
def slashdot_index(request):
result = resource_intensive_operation(request)
return view_for(result)

33. Reduce boilerplate..
try:
f = open('file1.txt')
for line in f:
print(line)
finally:
f.close()

34. .. with contexts
with open('file1.txt') as f:
for line in f:
print(line)

35. Generators
def public_files(dirname):
for fname in os.listdir(dirname):
if not fname.startswith('.'):
yield fname
for fname in public_files('.'):
open(fname)

36. Projicera data

37. Maskinellt procedurell
publicfiles = []
for fname in os.listdir('.'):
if not fname.startswith('.'):
publicfiles.append(open(fname))

38. Tillståndslös spaghetti
publicfiles = map(lambda fname: open(fname),
filter(lambda fname:
not fname.startswith('.'),
os.listdir('.')))

39. List comprehensions
publicfiles = [open(fname)
for fname in os.listdir('.')
if not fname.startswith('.')]

40. Generator comprehensions
publicfiles = (open(fname)
for fname in os.listdir('.')
if not fname.startswith('.'))

41. process(open(fname) for fname in os.listdir('.')
if not fname.startswith('.'))

42. Myter

43. "My way or the highway"

44. Sanningar

45. There should be one — and
preferably only one — obvious
way to do it.

46. Although that way may not be
obvious at first unless you're
Dutch.

47. Python is humanism

48. Python ger dig
● Enkel men kraftfull kod
● Fokus på lösningen

49. Tack!

50. Image Tributes (CC)
Python, Google, YouTube, Spotify logos & Amazon Python Day Poster photo courtesy of
respective organization.
Night train
"And so thy path shall be a track of light"
"Documents Reveal Django Pony, Caught In Tail Of Lies." / _why
"inch by inch"
"Wasserglas"
"I am Jack, hear me lumber!"
"Bend me, Shape me, any way you want me."