I apologize about being a total beginner with Ruby and Rails. I''ve
worked much more with PHP. I''m trying to read this code:
def save_order
@cart = find_cart
@order = Order.new(params[:order])
@order.line_items << @cart.items
if @order.save
@cart.empty!
redirect_to_index(@order.process_transaction)
else
render(:action => ''checkout'')
end
end
In the line
@order.line_items << @cart.items
what does the << mean?
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dblack-TKXtfPMJ4Ozk1uMJSBkQmQ@public.gmane.org
2006-Dec-03 01:05 UTC
Re: newbie question: how to read the "<<"
Hi -- On Tue, 21 Nov 2006, Jake Barnes wrote:> > I apologize about being a total beginner with Ruby and Rails. I''ve > worked much more with PHP. I''m trying to read this code: > > def save_order > @cart = find_cart > @order = Order.new(params[:order]) > @order.line_items << @cart.items > if @order.save > @cart.empty! > redirect_to_index(@order.process_transaction) > else > render(:action => ''checkout'') > end > end > > > In the line > > @order.line_items << @cart.items > > what does the << mean?It looks like an operator, but is actually a method. What you''re seeing is syntactic sugar for: @order.line_items.<<(@cart.items) For ActiveRecord collections, << adds a record to the collection, taking care of database manipulation behind the scenes. Do you have a Ruby language book? I can recommend one that covers all the things you''ve been asking about, and is optimized to give the best Ruby coverage for Rails developers :-) David -- David A. Black | dblack-TKXtfPMJ4Ozk1uMJSBkQmQ@public.gmane.org Author of "Ruby for Rails" [1] | Ruby/Rails training & consultancy [3] DABlog (DAB''s Weblog) [2] | Co-director, Ruby Central, Inc. [4] [1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com [2] http://dablog.rubypal.com | [4] http://www.rubycentral.org --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
puts "ab" << "c" #yields "abc" ["a", "b"] or with arrays: irb(main):001:0> ["a", "b"] << "c" => ["a", "b", "c"] On 12/2/06, dblack-TKXtfPMJ4Ozk1uMJSBkQmQ@public.gmane.org <dblack-TKXtfPMJ4Ozk1uMJSBkQmQ@public.gmane.org> wrote:> > Hi -- > > On Tue, 21 Nov 2006, Jake Barnes wrote: > > > > > I apologize about being a total beginner with Ruby and Rails. I''ve > > worked much more with PHP. I''m trying to read this code: > > > > def save_order > > @cart = find_cart > > @order = Order.new(params[:order]) > > @order.line_items << @cart.items > > if @order.save > > @cart.empty! > > redirect_to_index(@order.process_transaction) > > else > > render(:action => ''checkout'') > > end > > end > > > > > > In the line > > > > @order.line_items << @cart.items > > > > what does the << mean? > > It looks like an operator, but is actually a method. What you''re > seeing is syntactic sugar for: > > @order.line_items.<<(@cart.items) > > For ActiveRecord collections, << adds a record to the collection, > taking care of database manipulation behind the scenes. > > Do you have a Ruby language book? I can recommend one that covers all > the things you''ve been asking about, and is optimized to give the best > Ruby coverage for Rails developers :-) > > > David > > -- > David A. Black | dblack-TKXtfPMJ4Ozk1uMJSBkQmQ@public.gmane.org > Author of "Ruby for Rails" [1] | Ruby/Rails training & consultancy [3] > DABlog (DAB''s Weblog) [2] | Co-director, Ruby Central, Inc. [4] > [1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com > [2] http://dablog.rubypal.com | [4] http://www.rubycentral.org > > > >--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
> Do you have a Ruby language book? I can recommend one that covers all > the things you''ve been asking about, and is optimized to give the best > Ruby coverage for Rails developers :-) > > > David > > -- > David A. Black | dblack-TKXtfPMJ4Ozk1uMJSBkQmQ@public.gmane.org > Author of "Ruby for Rails" [1] | Ruby/Rails training & consultancy [3] > DABlog (DAB''s Weblog) [2] | Co-director, Ruby Central, Inc. [4] > [1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com > [2] http://dablog.rubypal.com | [4] http://www.rubycentral.orgI''d recommend the same book. It''s a great read. Bill -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Jakob Skjerning
2006-Dec-03 13:07 UTC
Re: [POSSIBLE SPAM] [Rails] newbie question: how to read the "<<"
On Nov 22, 2006, at 01:41 , Jake Barnes wrote:> In the line > > @order.line_items << @cart.items > > what does the << mean?It''s a method call, usually ''append'' and usually described in the API reference. In your specific case, I would guess it''s a method on some association, which means it''s documented in the Rails API: http://api.rubyonrails.org/classes/ActiveRecord/Associations/ ClassMethods.html#M000530 -- Jakob Skjerning - http://mentalized.net --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---