Regular Expressions

Slides of 'Kennislunch' presentation that I gave at Hoppinger HQ about Regular Expressions.

Transcript

1. Regular Expressions Magical string operations Voor de managers: ja het is technisch!
2. /(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a- z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01- \x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d- \x7f]|\\[\x01-\x09\x0b\x0c\x0e- \x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a- z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?| \[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9] [0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]? [0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01- \x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\ [\x01-\x09\x0b\x0c\x0e-\x7f])+)\])/
3. Flavors •POSIX Basic Regular Expressions (BRE) •POSIX Extended Regular Expressions (ERE) •Perl
4. if ( preg_match('/\.([^.]+)$/', $real_file, $matches) ) { $ext = strtolower($matches[1]); // do something with the extension }
5. if ( preg_match('/\.([^.]+)$/', $real_file, $matches) ) { $ext = strtolower($matches[1]); // do something with the extension }
6. /\.([^.]+)$/
7. /\.([^.]+)$/ Delimiters
8. /\.([^.]+)$/ Escaping
9. /\.([^.]+)$/ Negated character class
10. /\.([^.]+)$/ Repetition
11. /\.([^.]+)$/ Groups and backreferences $matches[1]
12. /\.([^.]+)$/ Anchors
13. Matching
14. • String comparison • "foo" == "foo" • "foo" == "bar" Matching
15. • String comparison • "foo" == "foo" • "foo" == "bar" • More complex • "foo bar baz" starts with "foo" • "foo bar baz" starts with "foo ", followed by one or more words that start with a "b" Matching
16. • String comparison • "foo" == "foo" • "foo" == "bar" • More complex • "foo bar baz" starts with "foo" /^foo/ • "foo bar baz" starts with "foo ", followed by one or more words that start with a "b" /^foo( b\w+)+$/ Matching
17. Characters Lorem ipsum dolor sit amet, consectetur adipiscing elit. /et/
18. Characters Lorem ipsum dolor sit amet, consectetur adipiscing elit. /et/
19. Escaping \^$.|?*+(){}[]
20. Escaping Lorem ipsum dolor sit amet, consectetur adipiscing elit. /\./
21. Escaping Lorem ipsum dolor sit amet, consectetur adipiscing elit. /\./
22. Character classes Lorem ipsum dolor sit amet, consectetur adipiscing elit. /[ie]t/
23. Character classes Lorem ipsum dolor sit amet, consectetur adipiscing elit. /[ie]t/
24. Character classes Lorem ipsum dolor sit amet, consectetur adipiscing elit. /[a-z]i/
25. Character classes Lorem ipsum dolor sit amet, consectetur adipiscing elit. /[a-z]i/
26. Character classes Lorem ipsum dolor sit amet, consectetur adipiscing elit. /[A-Fa-f0-9]/
27. Character classes Lorem ipsum dolor sit amet, consectetur adipiscing elit. /[^s ]i/
28. Character classes Lorem ipsum dolor sit amet, consectetur adipiscing elit. /[^s ]i/
29. Character classes /\d/ /[0-9]/ /\w/ /[A-Za-z0-9_]/ /\s/ /[ \t\r\n]/
30. Dot Lorem ipsum dolor sit amet, consectetur adipiscing elit. /./
31. Dot Lorem ipsum dolor sit amet, consectetur adipiscing elit. /./
32. Achors Lorem ipsum dolor sit amet, consectetur adipiscing elit. /t.$/
33. Achors Lorem ipsum dolor sit amet, consectetur adipiscing elit. /t.$/
34. Achors Lorem ipsum dolor sit amet, consectetur adipiscing elit. /^.o/
35. Achors Lorem ipsum dolor sit amet, consectetur adipiscing elit. /^.o/
36. Achors Lorem ipsum dolor sit amet, consectetur adipiscing elit. /r\b/
37. Achors Lorem ipsum dolor sit amet, consectetur adipiscing elit. /r\b/
38. Alternation Lorem ipsum dolor sit amet, consectetur adipiscing elit. /ipsum|dolor/
39. Alternation Lorem ipsum dolor sit amet, consectetur adipiscing elit. /ipsum|dolor/
40. Repetition Lorem ipsum dolor sit amet, consectetur adipiscing elit. /amei?t/
41. Repetition Lorem ipsum dolor sit amet, consectetur adipiscing elit. /amei?t/
42. Repetition Lorem ipsum dolor sit amet, consectetur adipiscing elit. /i.+m/
43. Repetition Lorem ipsum dolor sit amet, consectetur adipiscing elit. /i.+m/
44. Repetition Lorem ipsum dolor sit amet, consectetur adipiscing elit. /i.+m/
45. Repetition Lorem ipsum dolor sit amet, consectetur adipiscing elit. /doloa*r/
46. Repetition Lorem ipsum dolor sit amet, consectetur adipiscing elit. /doloa*r/
47. Repetition /.?/ /.{0,1}/ /.+/ /.{1,}/ /.*/ /.{0,}/ /.../ /.{3}/
48. Grouping Lorem ipsum dolor sit amet, consectetur adipiscing elit. /(.o)lor/
49. Grouping Lorem ipsum dolor sit amet, consectetur adipiscing elit. /(.o)lor/
50. Grouping Lorem ipsum dolor sit amet, consectetur adipiscing elit. /(.o)*r/
51. Backreferences Lorem ipsum dolor sit amet, consectetur adipiscing elit. /(.o)\1r/
52. Backreferences Lorem ipsum dolor sit amet, consectetur adipiscing elit. /(.o)\1r/
53. if ( preg_match('/\.([^.]+)$/', $real_file, $matches) ) { $ext = strtolower($matches[1]); // do something with the extension }
54. Grouping Lorem ipsum dolor sit amet, consectetur adipiscing elit. /(?:.o)*r/
55. Grouping Lorem ipsum dolor sit amet, consectetur adipiscing elit. /(?:.o)*r/
56. How far to go? /\b(?:\d{1,3}\.){3}\d{1,3}\b/
57. How far to go? /\b(?:\d{1,3}\.){3}\d{1,3}\b/ 999.999.999.999
58. How far to go? /\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9] [0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]? [0-9][0-9]?)\b/
59. /(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a- z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01- \x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d- \x7f]|\\[\x01-\x09\x0b\x0c\x0e- \x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a- z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?| \[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9] [0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]? [0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01- \x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\ [\x01-\x09\x0b\x0c\x0e-\x7f])+)\])/
60. /(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a- z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01- \x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d- \x7f]|\\[\x01-\x09\x0b\x0c\x0e- \x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a- z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?| \[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9] [0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]? [0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01- \x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\ [\x01-\x09\x0b\x0c\x0e-\x7f])+)\])/ RFC 2822
61. /[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!# $%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a- z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a- z0-9-]*[a-z0-9])?/
62. /[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!# $%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a- z0-9-]*[a-z0-9])?\.)+(?:[A-Z]{2}|com|org| net|edu|gov|mil|biz|info|mobi|name|aero| asia|jobs|museum)\b/
63. Never trust user input
64. © xkcd.com/208
65. Questions? Speak now, or forever be silent