If there''s a way to do this, I would be very happy: let''s pretend that I have an array called folks holding several AR objects from a model called People: folks = [ <AR 1: name => "bob", sex => "m", age => 40>, <AR 2: name => "sam", sex => "m", age => 7>, <AR 3: name => "dee", sex => "f", age => 25> ] What i''ve always wanted to do was say something like: folks.names ...and get an array back with ["bob","sam","dee"]. It seems kind of cumbersome to write a loop to do this, especially when RoR is supposed to be all neato and cool. Am I missing something obvious or do I really have to use a loop? Thanks! -- Jason Frankovitz - jason-eoA58Jexub5zbRFIqnYvSA@public.gmane.org - http://www.seethroo.us/ work: (310) 601-8454 cell: (415) 254-4890 AIM/Skype: jfrankov --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
subimage interactive
2006-Dec-23 01:03 UTC
Re: my fantasy: instant array of AR attributes?
You could go about it a number of ways.
I like this method
folks.collect! { |person| person.name}
Now folks is an array of all of their names....
On 12/22/06, Jason Frankovitz
<jason-eoA58Jexub5zbRFIqnYvSA@public.gmane.org>
wrote:>
>
> If there''s a way to do this, I would be very happy:
>
> let''s pretend that I have an array called folks holding several AR
> objects from a model called People:
>
> folks = [ <AR 1: name => "bob", sex => "m",
age => 40>,
> <AR 2: name => "sam", sex => "m", age =>
7>,
> <AR 3: name => "dee", sex => "f", age =>
25> ]
>
> What i''ve always wanted to do was say something like:
>
> folks.names
>
> ...and get an array back with
["bob","sam","dee"].
>
>
> It seems kind of cumbersome to write a loop to do this, especially
> when RoR is supposed to be all neato and cool. Am I missing something
> obvious or do I really have to use a loop?
>
> Thanks!
>
> --
> Jason Frankovitz - jason-eoA58Jexub5zbRFIqnYvSA@public.gmane.org -
http://www.seethroo.us/
> work: (310) 601-8454
> cell: (415) 254-4890
> AIM/Skype: jfrankov
>
>
> >
>
--
seth at subimage interactive
http://www.subimage.com/sublog/
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subimage interactive wrote:> You could go about it a number of ways. > > I like this method > > folks.collect! { |person| person.name}Doesn''t Rails provide a shortcut: folks.collect(&:name) ? -- Phlip http://www.greencheese.us/ZeekLand <-- NOT a blog!!! --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
dblack-TKXtfPMJ4Ozk1uMJSBkQmQ@public.gmane.org
2006-Dec-23 01:22 UTC
Re: my fantasy: instant array of AR attributes?
Hi -- On Fri, 22 Dec 2006, Phlip wrote:> > subimage interactive wrote: > >> You could go about it a number of ways. >> >> I like this method >> >> folks.collect! { |person| person.name} > > Doesn''t Rails provide a shortcut: > > folks.collect(&:name) > > ?Yes, and actually the thing that makes it work (Symbol#to_proc) is in 1.9: $ /usr/local/lib/ruby-cvs/bin/ruby -ve ''puts [1,2,3].map(&:to_f)'' ruby 1.9.0 (2006-12-09 patchlevel 0) [i686-linux] 1.0 2.0 3.0 David -- Q. What''s a good holiday present for the serious Rails developer? A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black) aka The Ruby book for Rails developers! Q. Where can I get Ruby/Rails on-site training, consulting, coaching? A. Ruby Power and Light, LLC (http://www.rubypal.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 -~----------~----~----~----~------~----~------~--~---
Even shorter: names = folks.collect(&:name) -christos On 23 Dec 2006, at 02:03, subimage interactive wrote:> You could go about it a number of ways. > > I like this method > > folks.collect! { |person| person.name} > > Now folks is an array of all of their names.... > > On 12/22/06, Jason Frankovitz <jason-eoA58Jexub5zbRFIqnYvSA@public.gmane.org> wrote: > > If there''s a way to do this, I would be very happy: > > let''s pretend that I have an array called folks holding several AR > objects from a model called People: > > folks = [ <AR 1: name => "bob", sex => "m", age => 40>, > <AR 2: name => "sam", sex => "m", age => 7>, > <AR 3: name => "dee", sex => "f", age => 25> ] > > What i''ve always wanted to do was say something like: > > folks.names > > ...and get an array back with ["bob","sam","dee"]. > > > It seems kind of cumbersome to write a loop to do this, especially > when RoR is supposed to be all neato and cool. Am I missing something > obvious or do I really have to use a loop? > > Thanks! > > -- > Jason Frankovitz - jason-eoA58Jexub5zbRFIqnYvSA@public.gmane.org - http://www.seethroo.us/ > work: (310) 601-8454 > cell: (415) 254-4890 > AIM/Skype: jfrankov > > > > > > > > -- > seth at subimage interactive > http://www.subimage.com/sublog/ > > >--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
I love it! My fantasy has come true. Anyone got a handle on what the & does? I knew about collect but it alters the original array, which I want to avoid (shuold''ve said that in my first email, sorry). Thanks to everyone for the suggestions! -Jason -- Jason Frankovitz - jfrankov-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org work: (310) 601-8454 cell: (415) 254-4890 AIM/Skype: jfrankov On Dec 22, 2006, at 5:27 PM, Christos Zisopoulos wrote:> Even shorter: > > names = folks.collect(&:name) > > -christos > > >--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
dblack-TKXtfPMJ4Ozk1uMJSBkQmQ@public.gmane.org
2006-Dec-23 02:01 UTC
Re: my fantasy: instant array of AR attributes?
Hi -- On Fri, 22 Dec 2006, Jason Frankovitz wrote:> On Dec 22, 2006, at 5:27 PM, Christos Zisopoulos wrote: > >> Even shorter: >> >> names = folks.collect(&:name) >> > I love it! My fantasy has come true. Anyone got a handle on what the & does? > I knew about collect but it alters the original array, which I want to avoid > (shuold''ve said that in my first email, sorry).collect (aka map) doesn''t alter the original array, unless you use the ! version (collect! or map!). I think one of the people who replied did use that, but Christos''s version doesn''t. The & introduces a lambda (an anonymous function, technically an instance of Proc), to be used as the code block to go with the method call. For example, look at this: array = [1,2,3,4,5] array.map {|e| e * 10 } # [10,20,30,40,50] and now with a separate lambda: lam = lambda {|e| e * 10 } array.map &lam # [10,20,30,40,50] The reason it works with &:name is that Rails has a to_proc conversion method for symbols. That method gets called automatically when the & is applied. When you do &:name, you get a lambda that, if you wrote it out by hand, would look like this: lambda {|e| e.send(:name) } So -- the net effect of all of this is that this: folks.collect(&:name) calls collect on folks, with a code block (a lambda) that performs the function of calling the "name" method on each element in folks. The result is a second, result array, consisting of all the names. David -- Q. What''s a good holiday present for the serious Rails developer? A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black) aka The Ruby book for Rails developers! Q. Where can I get Ruby/Rails on-site training, consulting, coaching? A. Ruby Power and Light, LLC (http://www.rubypal.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 -~----------~----~----~----~------~----~------~--~---