http://snippets.dzone.com/posts Fri, 25 Jul 2008 21:27:47 GMT DZone Snippets: range code http://snippets.dzone.com/posts/show/4099 Takes an Array and turns consecutive integers into Range objects. <br /> <br /><code> <br />class Array <br /> def collapse_ranges <br /> return self if self.length <= 2 <br /> self.uniq! <br /> self.sort! rescue nil <br /> temp_array, return_array = [], [] <br /> self.each_with_index do |item, i| <br /> if item.respond_to?(:next) <br /> temp_array.push item <br /> if item.next != self[i + 1] <br /> return_array.concat 3 <= temp_array.length ? <br /> [temp_array.first..temp_array.last] : <br /> temp_array <br /> temp_array.clear <br /> end <br /> else <br /> return_array.concat 3 <= temp_array.length ? <br /> [temp_array.first..temp_array.last] : <br /> temp_array <br /> temp_array.clear <br /> return_array.push item <br /> end <br /> end <br /> return return_array <br /> end <br />end <br /></code> <br /> <br /><code> <br />>> [1, 3, 4, 5, 7, 8].collapse_ranges.join(', ') <br />=> 1, 3..5, 7, 8 <br />>> %w(a c d e g i j).collapse_ranges.join(', ') <br />=> a, c..e, g, i, j <br />>> [1, 2.5, 3, 4, 5].collapse_ranges.join(', ') <br />=> 1, 2.5, 3..5 <br />>> [1, 2, 3, 4, {:test => 'value'}, 5].collapse_ranges.join(', ') <br />=> 1..4, testvalue, 5 <br /></code> Sun, 03 Jun 2007 17:59:53 GMT http://snippets.dzone.com/posts/show/4099 sporkyy (Todd Sayre) http://snippets.dzone.com/posts/show/3322 This works fine for integers and letters. It should work for anything though, so long as Ruby can form an range from the first and last array items. <br /> <br /><code> <br />class Array <br /> def missing_items <br /> return [] if self.length <= 1 <br /> self.uniq! <br /> self.sort! rescue nil <br /> begin <br /> (self.first..self.last).to_a - self <br /> rescue <br /> [] <br /> end <br /> end <br />end <br /></code> <br /> <br /><code> <br />>> [1, 3, 4, 10].missing_items.join(', ') <br />=> 2, 5, 6, 7, 8, 9 <br />>> [1, 2, 7, 7.5, 8.2].missing_items.join(', ') <br />=> 3, 4, 5, 6, 8 <br />>> %w(a b c f g j).missing_items.join(', ') <br />=> d, e, h, i <br />>> [2.5, {:test => 'value'}].missing_items.join(', ') <br />=> <br /></code> Thu, 18 Jan 2007 08:15:54 GMT http://snippets.dzone.com/posts/show/3322 sporkyy (Todd Sayre)