# Ruby on rails book, fundamental question **URL:** \ **Category:** Rails\ **Created:** [April 17, 2006, 2:49pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984 "2006-04-17T14:49:36Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![jan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ce7236/32.png) [@jan](https://www.ruby-forum.com/u/jan)\ **Post date:** [April 17, 2006, 2:49pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984/1 "2006-04-17T14:49:36Z")
Hi guys, bought the ROR book. I understand most of it and really like it. There is just on thing I just dont get. Lets take this code for example. def list @products = paginate :product, :per\_page =\> 10 end As far as I understand @products should be some kinda hash or array, with the data of the Database inside. How can I display this array ? One solution is to do it like this (like in the book) \<% for product in @products -%\> ![]() \<% end %\> But I want to understand (!) how this works. Something like puts @products[“title”] or puts @products[:title] which obviously doesnt work. I think this would help to understand the whole concept. Thanks alot ---
**Author:** ![jan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ce7236/32.png) [@jan](https://www.ruby-forum.com/u/jan)\ **Post date:** [April 17, 2006, 2:58pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984/2 "2006-04-17T14:58:36Z")
I will try to explain this. If you do the same command from ./script/console “@products = Product.find(:all)”, you will be able to access this hash by calling each element as @products[1].title or by other keys in the hash. Does that make since? John ---
**Author:** ![jan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ce7236/32.png) [@jan](https://www.ruby-forum.com/u/jan)\ **Post date:** [April 17, 2006, 3:04pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984/3 "2006-04-17T15:04:57Z")
Hi John, I just found this out myself about 1 Minute ago. Totally makes sense. Makes things much clearer. I have one more question though In the rhtml file you find something like this \<%= link\_to ‘Show’, :action =\> ‘show’, :id =\> product %\> in a controller you find: def show @product = Product.find(@params[:id]) end Everything makes sense. Im just not shure where the @params comes from. Is this some part of the framework ? Thanks alot again… 😉 John H. wrote: > I will try to explain this. If you do the same command from > ./script/console “@products = Product.find(:all)”, you will be able to > access this hash by calling each element as @products[1].title or by > other > keys in the hash. Does that make since? > > John ---
**Author:** ![jan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ce7236/32.png) [@jan](https://www.ruby-forum.com/u/jan)\ **Post date:** [April 17, 2006, 3:20pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984/4 "2006-04-17T15:20:10Z")
The @params would be the parameter’s that you pass with the :id =\> product or if you pass other params as well. On the other question the only way that I know how to print a whole array is with the @products.each or for product in @products. Hope that helps, John ---
**Author:** ![jan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ce7236/32.png) [@jan](https://www.ruby-forum.com/u/jan)\ **Post date:** [April 17, 2006, 3:06pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984/5 "2006-04-17T15:06:56Z")
I forgot. Is there a command in ruby to output the whole array ? Just for me to check ? ---
**Author:** ![jan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ce7236/32.png) [@jan](https://www.ruby-forum.com/u/jan)\ **Post date:** [April 17, 2006, 3:44pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984/6 "2006-04-17T15:44:52Z")
2006/4/17, Jan [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > I forgot. Is there a command in ruby to output the whole array ? > Just for me to check ? Try my\_array.inspect, that should do what you’re after. hth, Douglas ---
**Author:** ![jan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ce7236/32.png) [@jan](https://www.ruby-forum.com/u/jan)\ **Post date:** [April 17, 2006, 4:49pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984/7 "2006-04-17T16:49:38Z")
Douglas, Thanks for the inspect command. I had never seen that, it will be real helpful now. ---
**Author:** ![jan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ce7236/32.png) [@jan](https://www.ruby-forum.com/u/jan)\ **Post date:** [April 17, 2006, 4:37pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984/8 "2006-04-17T16:37:13Z")
Also of interest might be logger.info @product which will write out the array to the relevant log file or something like p @product will print out the array (regardless of if the content is a string or not) to the console running webrick ---
**Author:** ![jan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/ce7236/32.png) [@jan](https://www.ruby-forum.com/u/jan)\ **Post date:** [April 17, 2006, 5:39pm UTC](https://www.ruby-forum.com/t/ruby-on-rails-book-fundamental-question/57984/9 "2006-04-17T17:39:21Z")
@products is an array of Product objects. In your code you are iterating through the array and for each Product object you are accessing the attribute image\_url. @products[“title”] would be trying to access an array with a string as the index, which doesn’t work (this would work with a hash though). Jan wrote: > As far as I understand @products should be some kinda hash or array, > @products[“title”] or puts @products[:title] which obviously doesnt > work. > > I think this would help to understand the whole concept. > > Thanks alot – Sau S. [http://blog.saush.com](http://blog.saush.com) [http://read.saush.com](http://read.saush.com) [http://jaccal.sourceforge.net](http://jaccal.sourceforge.net)