Convert seconds into HH:MM:SS or date format in Ruby

convert-seconds-into-date-format-in-ruby.rb

# seconds
t = 236 
Time.at(t).utc.strftime("%H:%M:%S")
=> "00:03:56"

# unix time
t = 1450236594 
Time.at(t).utc.strftime("%Y/%d/%d %H:%M:%S")
=> "03:29:54"

# with timezone
class Time 
  def timezone(timezone = 'UTC')
    old = ENV['TZ']
    utc = self.dup.utc
    ENV['TZ'] = timezone
    output = utc.localtime
    ENV['TZ'] = old
    output
  end
end
Time.at(1450236594).timezone('Asia/Tokyo').to_datetime
Time.at(1450236594).timezone('Asia/Tokyo').strftime("%Y/%d/%d %H:%M:%S")

# Reference
# http://stackoverflow.com/questions/3963930/ruby-rails-how-to-convert-seconds-to-time
# http://qiita.com/semind/items/9614ded891d6154e9a06