Regular Expression Pocket Reference, 2nd Edition

Examples

Example 1-21. Simple match

#Find Spider-Man, Spiderman, SPIDER-MAN, etc.

dailybugle = 'Spider-Man Menaces City!'

if dailybugle.match(/spider[- ]?man./i)
    puts dailybugle
end

Example 1-22. Match and capture group

#Match dates formatted like MM/DD/YYYY, MM-DD-YY,...

date = '12/30/1969'

regexp = Regexp.new('^(\d\d)[-/](\d\d)[-/](\d\d(?:\d\d)?)$')
if md = regexp.match(date)
  month = md[1] #12
  day   = md[2] #30
  year  = md[3] #1969
end

Example 1-23. Simple substitution

#Convert <br> to <br /> for XHTML compliance

text  = 'Hello world. <br>'
regexp = Regexp.new('<br>', Regexp::IGNORECASE)

result = text.sub(regexp, "<br />")

Example 1-24. Harder substitution

#urlify - turn URLs into HTML links
text = 'Check the web site, http://www.oreilly.com/catalog/regexppr.'

regexp =  Regexp.new('
        \b                    # start at word boundary
        (                           # capture to \1
        (https?|telnet|gopher|file|wais|ftp) :
                                    # resource and colon
        [\w/#~:.?+=&%@!\-] +?       # one or more valid chars
                                    # take little as possible
        )
        (?=                         #  lookahead
        [.:?\-] *                   #  for possible punc
        (?: [^\w/#~:.?+=&%@!\-]     #  invalid character
        | $ )                       #  or end of string
        )', Regexp::EXTENDED)


result = text.sub(regexp, '<a href="\1">\1</a>')