Rails - Apr 2006 - ruby on rails book, fundamental question

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 -%>
        <img src="<%= product.image_url %>"/>
<% 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

-- 
Posted via http://www.ruby-forum.com/.

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

On 4/17/06, Jan <shocktone@lycos.de> wrote:
>
> 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 -%>
>         <img src="<%= product.image_url %>"/>
> <% 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
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>


--
John Hornbeck
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
http://wrath.rubyonrails.org/pipermail/rails/attachments/20060417/0704f9b2/attachment.html

If you write out the loop in long hand it makes more sense.

for each item in products array

item dot title 
next item

If you know the id in particular you want to show you can do item[1].title
otherwise you have to loop through them.

--------- Original Message --------
From: rails@lists.rubyonrails.org
To: rails@lists.rubyonrails.org <rails@lists.rubyonrails.org>
Subject: Re: [Rails] ruby on rails book, fundamental question
Date: 17/04/06 17:58
> I will try to explain this.&nbsp; If you do the same command from
./script/console &quot;@products = Product.find(:all)&quot;, you will be
able to access this hash by calling each element as @products[1].title or by
other keys in the hash.&nbsp; Does that make since?
> JohnOn 4/17/06, Jan &lt;shocktone@lycos.de&gt; wrote:
> Hi guys,bought the ROR book. I understand most of it and really like it.
Thereis just on thing I just dont get.Lets take this code for example.def
list&nbsp;&nbsp; @products = paginate :product, :per_page =&gt;
10
> endAs 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)
> &lt;% for product in @products
-%&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;img
src=&quot;&lt;%= product.image_url %&gt;&quot;/&gt;&lt;%
end %&gt;But I want
to understand (!) how this works. Something like
puts@products[&quot;title&quot;] or puts @products[:title] which
obviously
doesnt
> work.I think this would help to understand the whole concept.Thanks
alot--Posted via
http://www.ruby-forum.com/._______________________________________________
> Rails mailing
listRails@lists.rubyonrails.orghttp://lists.rubyonrails.org/mailman/listinfo/rails
> -- John Hornbeck
>
>
>
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

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 %><br/>

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 Hornbeck 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

-- 
Posted via http://www.ruby-forum.com/.

I forgot. Is there a command in ruby to output the whole array ?
Just for me to check ?

-- 
Posted via http://www.ruby-forum.com/.

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

On 4/17/06, Jan <shocktone@lycos.de> wrote:
>
> I forgot. Is there a command in ruby to output the whole array ?
> Just for me to check ?
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>


--
John Hornbeck
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
http://wrath.rubyonrails.org/pipermail/rails/attachments/20060417/90afddb9/attachment-0001.html

2006/4/17, Jan <shocktone@lycos.de>:
> 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

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


On 17 Apr 2006, at 16:43, Douglas Livingstone wrote:
> 2006/4/17, Jan <shocktone@lycos.de>:
>> 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
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

Douglas,

Thanks for the inspect command.  I had never seen that, it will be real
helpful now.

On 4/17/06, John Evans <junk.3eyes@gmail.com>
wrote:
>
> 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
>
>
> On 17 Apr 2006, at 16:43, Douglas Livingstone wrote:
>
> > 2006/4/17, Jan <shocktone@lycos.de>:
> >> 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
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>


--
John Hornbeck
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
http://wrath.rubyonrails.org/pipermail/rails/attachments/20060417/99bea8af/attachment-0001.html

@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:
> 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 -%>
>         <img src="<%= product.image_url %>"/>
> <% 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
>
>   

-- 
Sau Sheong

http://blog.saush.com
http://read.saush.com
http://jaccal.sourceforge.net