![It is the only language co-designed for the
most advanced and the complete novice.
[David Goodger]](https://image.slidesharecdn.com/python-utan-stodhjul-motorsag-110525063253-phpapp01/85/Python-utan-stodhjul-motorsag-3-320.jpg)
![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)](https://image.slidesharecdn.com/python-utan-stodhjul-motorsag-110525063253-phpapp01/85/Python-utan-stodhjul-motorsag-17-320.jpg)
![Effektivt
tokens = ['a', 'b', 'c', 'B', 'dd', 'C', 'DD']
similar = {}
for token in tokens:
key = token.lower()
similar.setdefault(key, []).append(token)](https://image.slidesharecdn.com/python-utan-stodhjul-motorsag-110525063253-phpapp01/85/Python-utan-stodhjul-motorsag-19-320.jpg)
![Generella behållare
● list() == []
● dict() == {}
● tuple() == ()
● set()](https://image.slidesharecdn.com/python-utan-stodhjul-motorsag-110525063253-phpapp01/85/Python-utan-stodhjul-motorsag-21-320.jpg)
![Python är interaktivt
$ python
Python 2.7.1 [...]
Type "help", "copyright", "credits" or "license" for
more information.
>>>](https://image.slidesharecdn.com/python-utan-stodhjul-motorsag-110525063253-phpapp01/85/Python-utan-stodhjul-motorsag-22-320.jpg)
![Maskinellt procedurell
publicfiles = []
for fname in os.listdir('.'):
if not fname.startswith('.'):
publicfiles.append(open(fname))](https://image.slidesharecdn.com/python-utan-stodhjul-motorsag-110525063253-phpapp01/85/Python-utan-stodhjul-motorsag-37-320.jpg)
![List comprehensions
publicfiles = [open(fname)
for fname in os.listdir('.')
if not fname.startswith('.')]](https://image.slidesharecdn.com/python-utan-stodhjul-motorsag-110525063253-phpapp01/85/Python-utan-stodhjul-motorsag-39-320.jpg)
Python utan-stodhjul-motorsag
- 1. Utan stödhjul och motorsåg
- 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)
- 7. Användare
- 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
- 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
- 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.
- 49. Tack!