scottfirestone / regular-expression-knowledge-we-have-discovered

Regular expression... oh, go read the project name -.^

Knowledge we have discovered about regular expressions:

Methods

• =~ Gives the index of the first match
• [] return the first match
• gsub FIND ME
• split FIND ME
• scan Returns an array of matches

Things that can be in a regular expression

• /P/ A character, anywhere in the string
• /PM/ Two characters next to each other
• /M+/ One or more of its target
• /M*/ Zero or more of its target
• /./ match any character

Still unknown

• [abc] A single character of: a, b, or c
• [^abc] Any single character except: a, b, or c
• [a-z] Any single character in the range a-z
• [a-zA-Z] Any single character in the range a-z or A-Z
• ^ Start of line
• $ End of line
• \A Start of string
• \z End of string
• \s Any whitespace character
• \S Any non-whitespace character
• \d Any digit
• \D Any non-digit
• \w Any word character (letter, number, underscore)
• \W Any non-word character
• \b Any word boundary
• (...) Capture everything enclosed
• (a|b) a or b
• a? Zero or one of a
• a* Zero or more of a
• a+ One or more of a
• a{3} Exactly 3 of a
• a{3,} 3 or more of a
• a{3,6} Between 3 and 6 of a

Open questions:

• does case matter?
• can we get rid of the plus in scan?

END $ curl -i google.com HTTP/1.1 301 Moved Permanently Location: http://www.google.com/ Content-Type: text/html; charset=UTF-8 Date: Thu, 07 Jan 2016 16:49:09 GMT Expires: Sat, 06 Feb 2016 16:49:09 GMT Cache-Control: public, max-age=2592000 Server: gws Content-Length: 219 X-XSS-Protection: 1; mode=block X-Frame-Options: SAMEORIGIN

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