Regex with optional groups. Useful for pulling out information about what you are looking for and where you are looking for it. For example: police records near sacramento, ca

address_extraction_regex.rb

# Uses this regex: ^((?:(?!(?:near|in)).)*)(?:(?:near|in)\s*(.*))?$

irb(main):001:0> /^((?:(?!(?:near|in)).)*)(?:(?:near|in)\s*(.*))?$/.match('police records near sacramento, ca')
=> #<MatchData "police records near sacramento, ca" 1:"police records " 2:"sacramento, ca">
irb(main):002:0> r=/^((?:(?!(?:near|in)).)*)(?:(?:near|in)\s*(.*))?$/.match('police records near sacramento, ca')
=> #<MatchData "police records near sacramento, ca" 1:"police records " 2:"sacramento, ca">
irb(main):003:0> r[0]
=> "police records near sacramento, ca"
irb(main):004:0> r[1]
=> "police records "
irb(main):005:0> r[2]
=> "sacramento, ca"
irb(main):006:0>