# File lib/ajaxim_string.rb, line 8
  def strtr(replace_pairs)
    keys = replace_pairs.map {|a, b| a }
    values = replace_pairs.map {|a, b| b }
    self.gsub(
      /(#{keys.map{|a| Regexp.quote(a) }.join( ')|(' )})/
      ) { |match| values[keys.index(match)] }
  end