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Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity
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Character Encoding & Unicode - How to (╯°□°)╯︵ ┻━┻ with dignity

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Every developer will inevitably feel the pain of character encoding issues. We will cover the fundamentals every Python developer should know on character encoding and Unicode. We will teach you how …

Every developer will inevitably feel the pain of character encoding issues. We will cover the fundamentals every Python developer should know on character encoding and Unicode. We will teach you how to identify the types of problems that occur when dealing with character encoding and outline a set of best practices and useful libraries which can be used to avoid and fix character encoding issues.

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  • Just saw the talk and it was great, even after having seen Ned's talk. Just a couple of comments: First, you both talked fairly quickly. In a couple of cases, key points sailed right by me. Fortunately I could replay a few minutes but this was probably harder to do in person. Second, Esther, please stand still on stage. I was trying to concentrate on the screen and my eyes kept being drawn to a person swaying on the side. I know that public speaking makes my heart run about 160 mph, and I assume it's the same for others, but maybe knowing about this will help. Again, the talk was great; I may even watch it again. So much clear information in such a short time - many thanks.
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  • 1. ODE TO A SHIPPING LABEL! by Carlos Bueno! ! Once there was a little o,! with an accent on top like só.! ! It started out as UTF8,! (universal since '98),! but the program only knew latin1,! and changed little ó to "ó" for fun.! ! A second program saw the "ó"! and said "I know HTML entity!"! So "ó" was smartened to "ó"! and passed on through happily.! ! Another program saw the tangle! (more precisely, ampersands to mangle)! and thus the humble "ó"! became "ó"
  • 2. Character Encoding & Unicode How to (╯°□°)╯︵ ┻━┻ with dignity Esther Nam & Travis Fischer! PyCon US 2014, Montréal
  • 3. Uni-wat?!
  • 4. ┻━┻ ︵ヽ ノ︵ ┻━┻
  • 5. How to (╯°□°)╯︵ ┻━┻ with dignity
  • 6. – Luke Sneeringer | Program Committee Chair “You'll be pleased to know that your talk title crashed our meeting robot, which is a great argument for the relevance of this talk. :-) ...”
  • 7. Python 3 is out of scope
  • 8. The Fundamentals of Unicode
  • 9. Humans use text. Computers speak bytes.
  • 10. a -> 01100001
  • 11. ASCII ISO-8859-15! (latin-9) CP-1252! (Windows 1252) UTF-8 a 01100001 01100001 01100001 01100001 € NA 10100100 10000000 11100010 10000010 10101100 ¤ NA NA 10100100 11000010 10100100
  • 12. ASCII ISO-8859-15! (latin-9) CP-1252! (Windows 1252) UTF-8 a 01100001 01100001 01100001 01100001 € NA 10100100 10000000 11100010 10000010 10101100 ¤ NA NA 10100100 11000010 10100100
  • 13. ASCII ISO-8859-15! (latin-9) CP-1252! (Windows 1252) UTF-8 a 01100001 01100001 01100001 01100001 € NA 10100100 10000000 11100010 10000010 10101100 ¤ NA NA 10100100 11000010 10100100
  • 14. ASCII ISO-8859-15! (latin-9) CP-1252! (Windows 1252) UTF-8 a 01100001 01100001 01100001 01100001 € NA 10100100 10000000 11100010 10000010 10101100 ¤ NA NA 10100100 11000010 10100100
  • 15. π — ‽ ☠ ☁ ☂ ☃ ☄ ★ ☆ ☇ ☈ ☉ ☊ ☋ ☌ ☍ ☎ ☏ ☐ ☑ ☒ ☓ ☘ ☙ ☚ ☛ ☜ ☝ ☞ ☟ ☠ ☡ ☢ ☣ ☤ ☥ ☦ ☧ ☨ ☩ ☪ ☫ ☬ ☭ ☮ ☯ ☸ ☹ ☺ ☻ ☼ ☽ ☾ ☿ ♀ ♁ ♂ ♃ ♄ ♅ ♆ ♇ ♔ ♕ ♖ ♗ ♘ ♙ ♚ ♛ ♜ ♝ ♞ ♟ ♠ ♡ ♢ ♣ ♤ ♥ ♦ ♧ ♨ ♩ ♪ ♫ ♬ ♭ ♯ ♰ ♾ ⚀ ⚁ ⚂ ⚃ ⚄ ⚅ ⚆ ⚇ ⚈
  • 16. a -> U+0061 Character Unicode Code Point
  • 17. ! Unicode a -> U+0061 Character Unicode Code Point
  • 18. ! Unicode a -> U+0061 Character LATIN SMALL LETTER A
  • 19. Computers speak bytes.
  • 20. ! Unicode a ! U+0061 -> 01100001 Unicode Code Point Binary Encoding
  • 21. ! Unicode U+0061 -> 01100001 Unicode Code Point Binary Encodinga
  • 22. UTF-8 Unicode Transformation Format
  • 23. Unicode != UTF-8 Code Points Binary Encoding U+0061 01100001
  • 24. Layers of Abstraction
  • 25. • Display (Glyphs | Fonts) Let them eat cake!
  • 26. • Display (Glyphs | Fonts) Let them eat cake! ! • Text (Unicode | Code Points) U+0061
  • 27. • Display (Glyphs | Fonts) Let them eat cake! ! • Text (Unicode | Code Points) U+0061 ! • Storage (Binary | UTF-8) 01100001
  • 28. Unicode & Python [Python 2.7]
  • 29. str type >>>euro_bytestring = '€' ! >>>type(euro_bytestring) <type 'str'> [Python 2.7]
  • 30. unicode type # € code point >>>euro_unicode = u'u20ac' ! >>>type(euro_unicode) <type 'unicode'> [Python 2.7]
  • 31. Unicode Code points u'u20ac' ! Bytes UTF-8 'xe2x82xac' ! [Python 2.7]
  • 32. Unicode Code points u'u20ac' 'xe2x82xac'.decode('utf8') ! Bytes UTF-8 'xe2x82xac' ! [Python 2.7]
  • 33. Unicode Code points u'u20ac' 'xe2x82xac'.decode('utf8') ! Bytes UTF-8 'xe2x82xac' ! [Python 2.7]
  • 34. Unicode Code points u'u20ac' 'xe2x82xac'.decode('utf8') u'u20ac'.encode('utf8') ! Bytes UTF-8 'xe2x82xac' ! [Python 2.7]
  • 35. Unicode Code points u'u20ac' 'xe2x82xac'.becode('utf8') u'u20ac'.uncode('utf8') ! Bytes UTF-8 'xe2x82xac' ! [Python 2.7]
  • 36. You CANNOT infer an encoding from a bytestring
  • 37. #! /usr/bin/python # -*- coding: utf8 -*- ! # Opened file should be latin-1 encoded! # If it’s not, call tech support ASAP with open("input_file.csv") as input_file: Date: Wed, 11 Apr 2014 11:15:55 -0600
 To: foo@bar.com
 From: bar@foo.com Subject: Character encoding MIME-Version: 1.0 Content-Type: text/html; charset="UTF-8" <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE html PUBLIC “-//W3C//DTD …> <html xmlns="http://www.w3.org/1999/xhtml" …>
  • 38. Best Practices
  • 39. Example Application
  • 40. Author Review G. van Rossum If you decide to design your own car there are thousands sort of car… R. Ebert Every great car should feel new every time you drive it. L. Torvalds Volvo isn’t evil, they just make really crappy cars.
  • 41. Author Review G. van Rossum If you decide to design your own car there are thousands sort of car… R. Ebert Every great car should feel new every time you drive it. L. Torvalds Volvo isn’t evil, they just make really crappy cars. Application Processes Text
  • 42. Author Review G. van Rossum If you decide to design your own car there are thousands sort of car… R. Ebert Every great car should feel new every time you drive it. L. Torvalds Volvo isn’t evil, they just make really crappy cars. Application Processes Text PSQL
  • 43. Author Review G. van Rossum If you decide to design your own car there are thousands sort of car… R. Ebert Every great car should feel new every time you drive it. L. Torvalds Volvo isn’t evil, they just make really crappy cars. Application Processes Text PSQL
  • 44. Encoding: Windows 1252 (CP-1252)
  • 45. Montreal -> Montréal
  • 46. psql=# set server_encoding to "utf-8";
  • 47. My friend said: “I cannot believe this is a Volvo! I had a car just like this when I lived in Montreal.” He told me he had paid 9400€ for his. Sample Review Text
  • 48. My friend said: “I cannot believe this is a Volvo! I had a car just like this when I lived in Montreal.” He told me he had paid 9400€ for his. Sample Review Text
  • 49. My friend said: “I cannot believe this is a Volvo! I had a car just like this when I lived in Montreal.” He told me he had paid 9400€ for his. Sample Review Text
  • 50. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 51. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 52. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 53. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 54. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 55. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 56. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 57. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review)
  • 58. My friend said: �I cannot believe this is a Volvo! I had a car just like this when I lived in Montréal.� He told me he had paid 9400� for his. Output from UTF-8 encoded PSQL database
  • 59. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 60. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 61. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 62. [Python 2.7] # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review)
  • 63. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 64. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 65. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 66. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 67. My friend said: “I cannot believe this is a Volvo! I had a car just like this when I lived in Montreal.” He told me he had paid 9400€ for his. Original CP-1252 Data
  • 68. My friend said: “I cannot believe this is a Volvo! I had a car just like this when I lived in Montréal.” He told me he had paid 9400€ for his. Mixed CP-1252 & UTF-8
  • 69. My friend said: �I cannot believe this is a Volvo! I had a car just like this when I lived in Montréal.� He told me he had paid 9400� for his. Interpreted as UTF-8 by database
  • 70. Know your encodings Best Practice #1
  • 71. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 72. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: ! author, date, review_text = row_text.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 73. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode() author, date, review_text = unicode_row.split(",") converted_review = review_text.replace("Montreal", "Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 74. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode() author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 75. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode() author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable, author, date, converted_review)
  • 76. Traceback (most recent call last): File "...", line ..., in <module> unicode_row = row_text.decode() UnicodeDecodeError: 'ascii' codec can't decode byte 0x93 in position 31: ordinal not in range(128)
  • 77. Traceback (most recent call last): File "...", line ..., in <module> unicode_row = row_text.decode() UnicodeDecodeError: 'ascii' codec can't decode byte 0x93 in position 31: ordinal not in range(128)
  • 78. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode() author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 79. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode() author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable, author, date, converted_review)
  • 80. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode("cp1252") author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 81. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode("cp1252") author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable, author, date, converted_review) [Python 2.7]
  • 82. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode("cp1252") author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable, author.encode("utf8"), date.encode("utf8"), converted_review.encode("utf8")) [Python 2.7]
  • 83. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode("cp1252") author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable author.encode("utf8" date.encode("utf8"), converted_review.encode("utf8")
  • 84. My friend said: “I cannot believe this is a Volvo! I had a car just like this when I lived in Montréal.” He told me he had paid 9400€ for his.
  • 85. Use the Unicode Sandwich Best Practice #2
  • 86. Decode as early as possible.! Unicode everywhere in the middle.! Encode as late as possible.
  • 87. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode("cp1252") author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable, author.encode("utf8"), date.encode("utf8"), converted_review.encode("utf8")) [Python 2.7]
  • 88. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode("cp1252") author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable, author.encode("utf8"), date.encode("utf8"), converted_review.encode("utf8")) [Python 2.7]
  • 89. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode("cp1252") author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u”Montreal", u"Montréal") DB.insert(ReviewTable, author.encode("utf8"), date.encode("utf8"), converted_review.encode("utf8")) [Python 2.7]
  • 90. Test Your (Text Related) Code Best Practice #3
  • 91. Test encoding ranges & boundaries test_strings = ['Hello Montreal!', '¡‫ן‬ɐǝɹʇuoɯ o‫ןן‬ǝɥ', 'ђєɭɭ๏ ๓๏ภՇгєค !'] ! func_under_test(test_strings)
  • 92. test_bytes = 'I am a bytestring mwahaha' ! test_unicode = u'ι αм υηι¢σ∂є!' ! ! i_expect_unicode(test_bytes) ! i_expect_bytes(test_unicode) Test interfaces against both Python text types
  • 93. def ascii_handling_function(ascii_str): ... ascii_str.decode('ascii') ... Test handling of incorrect encoding
  • 94. utf8_str = u'UՇF-8 ՇєsՇ'.encode('utf8') ! with assertRaises(UnicodeDecodeError): line = ascii_handling_function(utf8_str) Test handling of incorrect encoding
  • 95. Best Practices 1. Know your encodings 2. Use the Unicode sandwich 3. Test your (text related) code
  • 96. Issues We Can’t Control
  • 97. Incorrect encoding
  • 98. Author Review G. van Rossum If you decide to design your own car there are thousands sort of car… R. Ebert Every great car should feel new every time you drive it. L. Torvalds Volvo isn’t evil, they just make really crappy cars. Application Processes Text PSQL
  • 99. Declared as “CP-1252”! ! ! ! ! Is actually “UTF-8”
  • 100. # -*- coding: utf-8 -*- ! reviews_file = open("reviews_file.csv") ! for row_text in reviews_file: unicode_row = row_text.decode("cp1252") author, date, review_text = unicode_row.split(u",") converted_review = review_text.replace(u"Montreal", u"Montréal") DB.insert(ReviewTable author.encode("utf8" date.encode("utf8"), converted_review.encode("utf8")
  • 101. UnicodeDecodeError
  • 102. How to Deal • Ask
  • 103. How to Deal • Ask • Guess (with chardet library)
  • 104. How to Deal • Ask • Guess (with chardet library) • You wrote tests, right?
  • 105. Mixed encodings or corrupted bytes
  • 106. John Smith’s Autoplex ! Broken text&hellip; it&#x2019;s fantastic! ! Hello ^[[30m; World
  • 107. John Smith’s Autoplex ! Broken text&hellip; it&#x2019;s fantastic! ! Hello ^[[30m; World MOJIBAKE
  • 108. u"John Smith’s Autoplex"
  • 109. u"John Smith’s Autoplex" ! >>>u'John Smith’sAutoplex'.encode('cp1252')
  • 110. u"John Smith’s Autoplex" ! >>>u'John Smith’sAutoplex'.encode('cp1252') ! 'John Smithxe2x80x99s Autoplex' (bytestring)
  • 111. 'John Smithxe2x80x99s Autoplex' (bytestring)
  • 112. 'John Smithxe2x80x99s Autoplex' (bytestring) ! >>>'John Smithxe2x80x99s Autoplex' .decode('utf8') ! ! u'John Smith’s Autoplex'
  • 113. UTF8 U+2019 ! ’
  • 114. UTF8 xe2x80x99 U+2019 ! ’
  • 115. UTF8 xe2x80x99 U+2019 ! ’ U+00e2 ! â U+20ac ! € U+2122 ! ™ CP1252
  • 116. str_dealer = u"John Smith’s Autoplex" ! ! def manually_convert_encoding(str_dealer): """ Manually replace incorrect, UTF8-encoded bytes with CP1252 bytes for the same character """ ! str_dealer.replace('xe2x80x98', 'x91') # ‘ str_dealer.replace('xe2x80x99', 'x92') # ’ str_dealer.replace('xe2x80x9c', 'x93') # “ str_dealer.replace('xe2x80x9d', 'x94') # ” str_dealer.replace('xe2x80x94', 'x97') # — str_dealer.replace('xe2x84xa2', 'x99') # ™ str_dealer.replace('xe2x82xac', 'x80') # €
  • 117. dealer_name = u"John Smith’s Autoplex" ! >>> from ftfy import fix_text ! >>> fix_text(dealer_name) ! u"John Smith's Autoplex" python-ftfy fixes mojibake
  • 118. Target encoding can’t handle source data
  • 119. Source Data (UTF-8) Target Application Data (CP-1252) ?
  • 120. >>>u'☃ Brrrr!'.encode('cp1252', 'strict') ! Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/Users/esther/ENV/lib/python2.7/ encodings/cp1252.py", line 12, in encode return codecs.charmap_encode(input,errors,encoding_ table) UnicodeEncodeError: 'charmap' codec can't encode character u'u2603' in position 0: character maps to <undefined> [Python 2.7]
  • 121. >>>u'☃ Brrrr!'.encode('cp1252', 'ignore') ! ' Brrrr!' [Python 2.7]
  • 122. >>>u'☃ Brrrr!'.encode('cp1252', 'replace') ! '? Brrrr!' [Python 2.7]
  • 123. ! ! U+0004 END OF TRANSMISSION
  • 124. Cars.com / NewCars.com Tech Team ! SoCal Piggies ! Ned Batchelder (for his Pragmatic Unicode talk) Thank you ツ
  • 125. Pragmatic Unicode http://nedbatchelder.com/text/unipain.html ! The Absolute Minimum You Must Know http://www.joelonsoftware.com/articles/Unicode.html ! Chapter on Strings in “Dive into Python” by Mark Pilgrim http://getpython3.com/diveintopython3/strings.html ! General questions, relating to UTF or Encoding Form http://www.unicode.org/faq/utf_bom.html ! Unicode HOWTO (Python 2.7) http://docs.python.org/2/howto/unicode.html The fundamentals
  • 126. “Just what the dickens is ‘Unicode’?” https://pythonhosted.org/kitchen/unicode-frustrations.html
 Differences between these commonly confused encodings http://www.i18nqa.com/debug/table-iso8859-1-vs- windows-1252.html ! “Latin-1” in MySQL is more like “CP-1252” https://dev.mysql.com/doc/refman/5.0/en/charset-we-sets.html ! Why it's important to write tests with character boundary values http://labs.spotify.com/2013/06/18/creative-usernames/ Further reading
  • 127. chardet https://pypi.python.org/pypi/chardet ! python-ftfy https://github.com/LuminosoInsight/python-ftfy Tools
  • 128. @estherbester @travisfischer Slides at http://bit.ly/flip_tables IRC

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