重构If语句在Ruby中不那么冗长

Question

是否有更简洁的方式来构造以下if语句？

if self.itemsize.downcase.include? "a3" or 
   self.itemsize.downcase.include? "a4" or 
   self.itemsize.downcase.include? "a5" or 
   self.itemsize.downcase.include? "dl" 

  puts "yadda yadda"

end

也许有阵列？例如if self.itemsize.downcase.include? ["a3", "a4", "a5", "dl"]

Answer 1

size = itemsize.downcase # memoize
if %w(a3 a4 a5 dl).any? {|e| size.include? e}
  puts "yadda yadda"
end