Ruby 是動態語言,你可以改變 Ruby 程序的結構,功能,在Ruby程序運行中。方法、屬性可以被加入或去除,新的類或對象可以被建立,新的模塊可以出現。請看程序 E5.4-1.rb :
ruby 代碼
- # E5.4-1.rb
- class Person
- def talk
- puts "Today is Saturday. "
- end
- end
- p1=Person.new
- p1.talk # => Today is Saturday.
- class Person
- def talk
- puts "Today is #@date. "
- end
- attr_accessor :date
- end
- p1.date="Sunday"
- p1.talk # => Today is Sunday.
當然,除了修改方法,添加方法,你還可以除去方法。看程序 E5.4-2.rb :
ruby 代碼
- # E5.4-2.rb
- class Person
- def talk
- puts "Today is Saturday. "
- end
- end
- p1=Person.new
- p1.talk # => Today is Saturday.
- class Person
- undef :talk
- end
- #p1.talk talk方法已經不存在
Ruby 語言靈活,因爲 Ruby 是動態語言; Ruby 語言強大,因爲 Ruby 是動態語言; Ruby 語言初學者容易犯錯誤,也因爲 Ruby 是動態語言。
完整閱讀,請看我寫的 Ruby語言中文教程all in one