ruby Array.inspect 与 Array[element].to_s

Question

I'm working with an array, which we'll call books<\/code> , of complex objects, which we'll call Book<\/code> . The problem is when I call puts "#{books.inspect}"<\/code> , ruby outputs a stream of binary (unreadable utf8 characters). However, when I call puts #{books[0].to_str}"<\/code> , I get a brief, pretty output that describes the book<\/code> in question. Not sure if it is relevant, but Book<\/code> is a subclass (we can call it's parent class Item<\/code> ), and books.length=1<\/code>

[chk ~ ]$ ruby -v
ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-linux]

Answer 1

class Myclass
    def to_s
        'my string representation'
    end
    def inspect
        'my inspection'
    end
end
a= [Myclass.new]
p a
puts a

outputs ::
[my inspection]
my string representation

Answer 2

books.inspect<\/code> and books[0].to_s<\/code> are absolutely NOT the same. The first is a call to inspect<\/code> method of book<\/code> object, which is an array. The second is a call to to_s<\/code> method of books[0]<\/code> object, whatever it is that is contained inside the array. As you didn't specify what exactly is books[0]<\/code> , I'm afraid I can't tell anything more.

"

Answer 3

books<\/code> is an array so calling books.inspect<\/code> is calling Array#inspect<\/code> . That method works by calling .inspect<\/code> on the elements, so in this case Book#inspect<\/code> .

class MyClass
  def inspect
    'my string representation'
  end
  alias_method :to_s, :inspect
end