Not getting correct output from to_s

Question

One of the examples in Peter Cooper's Beginning Ruby for polymorphism involves the to_s method. He gives this example:

puts 1000.to_s
puts [1, 2, 3].to_s
puts ({ :name => 'Fred', :age => 10 }).to_s

and shows this as the output:

1000
123
age10nameFred

but the output I get is:

1000
[1, 2, 3]
{:name=>"Fred", :age=>10}

Does anyone know why this would be the case? Was there a change in ruby, or is there something I'm doing wrong? Or not enough info to tell? How can I find it out?

Answer 1

The examples work using ruby 1.8.7, which is getting a bit dated. Ruby 1.9.3 (the current version) changed the to_s implementation for Arrays and Hashes.

EDIT: See Ruby 1.9 Array.to_s behaves differently?