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KathysKode-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org

2008-Jun-18 21:41 UTC

DRYer way to see if array exists before I do a find?

Many times I perform logic where I look to gather an array of records,
but first must check to see if any exists (so I don''t get an error of
a .nil array).
Here is an example of some code I wrote to today, is there a
''sweeter''
way to achieve the same results? If so, I would use this style of
coding many times.
      unless project.vendors.nil?
        @vendors  = project.vendors.find(:all)
        for vendor in @vendors
          unless vendor.products.nil?
            @products = vendor.products.find(:all)
            for product in @products
              unless product.prodrevs.nil?
               @prodrevs = product.prodrevs.find(:all)
                for prodrev in @prodrevs
                  @prodrevmap << prodrev
                end
              end
            end
          end
        end
Thanks,
Kathleen
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Michael Breen

2008-Jun-18 22:18 UTC

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Re: DRYer way to see if array exists before I do a find?

ok, I''ll bite.

If the goal is get all prodrev''s what''s wrong with
Prodrev.find(:all)?


On Jun 18, 2008, at 5:41 PM, KathysKode-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
wrote:
>
> Many times I perform logic where I look to gather an array of records,
> but first must check to see if any exists (so I don''t get an error
of
> a .nil array).
> Here is an example of some code I wrote to today, is there a
''sweeter''
> way to achieve the same results? If so, I would use this style of
> coding many times.
>      unless project.vendors.nil?
>        @vendors  = project.vendors.find(:all)
>        for vendor in @vendors
>          unless vendor.products.nil?
>            @products = vendor.products.find(:all)
>            for product in @products
>              unless product.prodrevs.nil?
>               @prodrevs = product.prodrevs.find(:all)
>                for prodrev in @prodrevs
>                  @prodrevmap << prodrev
>                end
>              end
>            end
>          end
>        end
> Thanks,
> Kathleen
> >

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Marlon Moyer

2008-Jun-18 22:40 UTC

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Re: DRYer way to see if array exists before I do a find?

project.vendors.find(:all).each do |vendor|
	vendor.products.find(:all).each do |product|
		product.prodrevs.find(:all).each do |prodrev|
			@prodrevmap << prodrev
		end
	end
end


On Jun 18, 2008, at 4:41 PM, KathysKode-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
wrote:
>
> Many times I perform logic where I look to gather an array of records,
> but first must check to see if any exists (so I don''t get an error
of
> a .nil array).
> Here is an example of some code I wrote to today, is there a
''sweeter''
> way to achieve the same results? If so, I would use this style of
> coding many times.
>      unless project.vendors.nil?
>        @vendors  = project.vendors.find(:all)
>        for vendor in @vendors
>          unless vendor.products.nil?
>            @products = vendor.products.find(:all)
>            for product in @products
>              unless product.prodrevs.nil?
>               @prodrevs = product.prodrevs.find(:all)
>                for prodrev in @prodrevs
>                  @prodrevmap << prodrev
>                end
>              end
>            end
>          end
>        end
> Thanks,
> Kathleen
> >

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Rob Biedenharn

2008-Jun-18 23:28 UTC

head link

Re: DRYer way to see if array exists before I do a find?

On Jun 18, 2008, at 6:40 PM, Marlon Moyer wrote:> project.vendors.find(:all).each do |vendor|
> 	vendor.products.find(:all).each do |product|
> 		product.prodrevs.find(:all).each do |prodrev|
> 			@prodrevmap << prodrev
> 		end
> 	end
> end
>
>
> On Jun 18, 2008, at 4:41 PM,
KathysKode-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
>> Many times I perform logic where I look to gather an array of  
>> records,
>> but first must check to see if any exists (so I don''t get an
error of
>> a .nil array).
>> Here is an example of some code I wrote to today, is there a  
>> ''sweeter''
>> way to achieve the same results? If so, I would use this style of
>> coding many times.
>>     unless project.vendors.nil?
>>       @vendors  = project.vendors.find(:all)
>>       for vendor in @vendors
>>         unless vendor.products.nil?
>>           @products = vendor.products.find(:all)
>>           for product in @products
>>             unless product.prodrevs.nil?
>>              @prodrevs = product.prodrevs.find(:all)
>>               for prodrev in @prodrevs
>>                 @prodrevmap << prodrev
>>               end
>>             end
>>           end
>>         end
>>       end
>> Thanks,
>> Kathleen

That''s more compact, but why all the .find(:all) methods? 
You''re
looking for all the prodrevs under a project.  If I assume:

class Project;  has_many :vendors   ;end
class Vendor ;  has_many :products ;belongs_to :project ;end
class Product;  has_many :prodrevs ;belongs_to :vendor  ;end
class Prodrev;                      belongs_to :product ;end

You could:

class Prodrev
   def self.map_for_project(project_id)
     find(:all, :conditions => [''projects.id = ?'',
project_id],
          :select => ''prodrevs.*'', :readonly => false,
          :joins => [''JOIN products ON products.id =  
prodrevs.product_id'',
                     ''JOIN vendors  ON vendors.id  =  
products.vendor_id'',
                     ''JOIN projects ON projects.id =  
vendors.project_id''].join('' ''))
   end
end

@prodrevmap = Prodrev.map_for_project(project.id)

If you do this often, you''ll (most likely) benefit from letting the  
database do the joining for you and avoiding all the ActiveRecord  
objects that you''d otherwise create just to reach down to the Prodrevs.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org

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KathysKode-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org

2008-Jun-19 00:29 UTC

head link

Re: DRYer way to see if array exists before I do a find?

Marlon,
Your idea looks very sexy but I suspect that it won''t work if any of
the finds are unsuccessful. I tried the idea (below) and it seems to
look the best (so far).
I''m running this routine to calculate the .xml entries for a Google
Sitemap...so you should know that this is a special occurance that I''m
running as a RAKE job.
If anyone else is tasked with having to create a Google Sitemap on a
complex database, I''d be happy to share what I have so far.

# Begin - First set of records
    @prodrevmap = []
    @vendors  = project.vendors.find(:all) unless project.vendors.nil?
    for vendor in @vendors
      @products = vendor.products.find(:all) unless
vendor.products.nil?
      for product in @products
        @prodrevs = product.prodrevs.find(:all) unless
product.prodrevs.nil?
        for prodrev in @prodrevs
          @prodrevmap << prodrev
        end
      end
    end
# end - First set of records

Kathleen

On Jun 18, 4:40 pm, Marlon Moyer
<marlon.mo...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> project.vendors.find(:all).each do |vendor|
>         vendor.products.find(:all).each do |product|
>                 product.prodrevs.find(:all).each do |prodrev|
>                         @prodrevmap << prodrev
>                 end
>         end
> end
>
> On Jun 18, 2008, at 4:41 PM,
KathysK...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
>
>
>
>
>
> > Many times I perform logic where I look to gather an array of records,
> > but first must check to see if any exists (so I don''t get an
error of
> > a .nil array).
> > Here is an example of some code I wrote to today, is there a
''sweeter''
> > way to achieve the same results? If so, I would use this style of
> > coding many times.
> >      unless project.vendors.nil?
> >        @vendors  = project.vendors.find(:all)
> >        for vendor in @vendors
> >          unless vendor.products.nil?
> >            @products = vendor.products.find(:all)
> >            for product in @products
> >              unless product.prodrevs.nil?
> >               @prodrevs = product.prodrevs.find(:all)
> >                for prodrev in @prodrevs
> >                  @prodrevmap << prodrev
> >                end
> >              end
> >            end
> >          end
> >        end
> > Thanks,
> > Kathleen- Hide quoted text -
>
> - Show quoted text ---~--~---------~--~----~------------~-------~--~----~
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Michael Breen

2008-Jun-19 00:31 UTC

head link

Re: DRYer way to see if array exists before I do a find?

On Jun 18, 2008, at 8:29 PM, KathysKode-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
wrote:
> If anyone else is tasked with having to create a Google Sitemap on a
have you seen http://github.com/queso/sitemap/tree/master?

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Frederick Cheung

2008-Jun-19 10:24 UTC

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Re: DRYer way to see if array exists before I do a find?

On 19 Jun 2008, at 01:29, KathysKode-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
wrote:
>
> Marlon,
> Your idea looks very sexy but I suspect that it won''t work if any
of
> the finds are unsuccessful. I tried the idea (below) and it seems to
> look the best (so far).
find :all and associations that are collections always return an  
array, never nil

You might also try something like

Prodrev.find :all, :joins => {:product => {:vendor  
=> :project}}, :conditions => [''projects.id = ?'',
project.id]

Fred
>
> I''m running this routine to calculate the .xml entries for a
Google
> Sitemap...so you should know that this is a special occurance that
I''m
> running as a RAKE job.
> If anyone else is tasked with having to create a Google Sitemap on a
> complex database, I''d be happy to share what I have so far.
>
> # Begin - First set of records
>    @prodrevmap = []
>    @vendors  = project.vendors.find(:all) unless project.vendors.nil?
>    for vendor in @vendors
>      @products = vendor.products.find(:all) unless
> vendor.products.nil?
>      for product in @products
>        @prodrevs = product.prodrevs.find(:all) unless
> product.prodrevs.nil?
>        for prodrev in @prodrevs
>          @prodrevmap << prodrev
>        end
>      end
>    end
> # end - First set of records
>
> Kathleen
>
> On Jun 18, 4:40 pm, Marlon Moyer
<marlon.mo...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> project.vendors.find(:all).each do |vendor|
>>         vendor.products.find(:all).each do |product|
>>                 product.prodrevs.find(:all).each do |prodrev|
>>                         @prodrevmap << prodrev
>>                 end
>>         end
>> end
>>
>> On Jun 18, 2008, at 4:41 PM,
KathysK...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
>>
>>
>>
>>
>>
>>> Many times I perform logic where I look to gather an array of  
>>> records,
>>> but first must check to see if any exists (so I don''t get
an error
>>> of
>>> a .nil array).
>>> Here is an example of some code I wrote to today, is there a  
>>> ''sweeter''
>>> way to achieve the same results? If so, I would use this style of
>>> coding many times.
>>>      unless project.vendors.nil?
>>>        @vendors  = project.vendors.find(:all)
>>>        for vendor in @vendors
>>>          unless vendor.products.nil?
>>>            @products = vendor.products.find(:all)
>>>            for product in @products
>>>              unless product.prodrevs.nil?
>>>               @prodrevs = product.prodrevs.find(:all)
>>>                for prodrev in @prodrevs
>>>                  @prodrevmap << prodrev
>>>                end
>>>              end
>>>            end
>>>          end
>>>        end
>>> Thanks,
>>> Kathleen- Hide quoted text -
>>
>> - Show quoted text -
> >

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KathysKode-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org

2008-Jun-19 17:14 UTC

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Re: DRYer way to see if array exists before I do a find?

Mr. Cheung,
You are truly the ''Zen Master'' of Rails. Thank you for your
wonderful
example.
Kathleen

On Jun 19, 4:24 am, Frederick Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> On 19 Jun 2008, at 01:29,
KathysK...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
>
>
>
> > Marlon,
> > Your idea looks very sexy but I suspect that it won''t work if
any of
> > the finds are unsuccessful. I tried the idea (below) and it seems to
> > look the best (so far).
>
> find :all and associations that are collections always return an  
> array, never nil
>
> You might also try something like
>
> Prodrev.find :all, :joins => {:product => {:vendor  
> => :project}}, :conditions => [''projects.id = ?'',
project.id]
>
> Fred
>
>
>
>
>
> > I''m running this routine to calculate the .xml entries for a
Google
> > Sitemap...so you should know that this is a special occurance that
I''m
> > running as a RAKE job.
> > If anyone else is tasked with having to create a Google Sitemap on a
> > complex database, I''d be happy to share what I have so far.
>
> > # Begin - First set of records
> >    @prodrevmap = []
> >    @vendors  = project.vendors.find(:all) unless project.vendors.nil?
> >    for vendor in @vendors
> >      @products = vendor.products.find(:all) unless
> > vendor.products.nil?
> >      for product in @products
> >        @prodrevs = product.prodrevs.find(:all) unless
> > product.prodrevs.nil?
> >        for prodrev in @prodrevs
> >          @prodrevmap << prodrev
> >        end
> >      end
> >    end
> > # end - First set of records
>
> > Kathleen
>
> > On Jun 18, 4:40 pm, Marlon Moyer
<marlon.mo...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> >> project.vendors.find(:all).each do |vendor|
> >>         vendor.products.find(:all).each do |product|
> >>                 product.prodrevs.find(:all).each do |prodrev|
> >>                         @prodrevmap << prodrev
> >>                 end
> >>         end
> >> end
>
> >> On Jun 18, 2008, at 4:41 PM,
KathysK...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
>
> >>> Many times I perform logic where I look to gather an array of
 
> >>> records,
> >>> but first must check to see if any exists (so I don''t
get an error  
> >>> of
> >>> a .nil array).
> >>> Here is an example of some code I wrote to today, is there a  
> >>> ''sweeter''
> >>> way to achieve the same results? If so, I would use this style
of
> >>> coding many times.
> >>>      unless project.vendors.nil?
> >>>        @vendors  = project.vendors.find(:all)
> >>>        for vendor in @vendors
> >>>          unless vendor.products.nil?
> >>>            @products = vendor.products.find(:all)
> >>>            for product in @products
> >>>              unless product.prodrevs.nil?
> >>>               @prodrevs = product.prodrevs.find(:all)
> >>>                for prodrev in @prodrevs
> >>>                  @prodrevmap << prodrev
> >>>                end
> >>>              end
> >>>            end
> >>>          end
> >>>        end
> >>> Thanks,
> >>> Kathleen- Hide quoted text -
>
> >> - Show quoted text -- Hide quoted text -
>
> - Show quoted text ---~--~---------~--~----~------------~-------~--~----~
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Phillip Koebbe

2008-Jun-20 02:03 UTC

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Re: DRYer way to see if array exists before I do a find?

Frederick Cheung wrote:> Prodrev.find :all, :joins => {:product => {:vendor
> => :project}}, :conditions => [''projects.id = ?'',
project.id]
> 
> Fred
Hey Fred,

How''d you know I needed an example of a nested :joins statement?

:)

Peace,
Phillip
-- 
Posted via http://www.ruby-forum.com/.

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Rails - Jun 2008 - DRYer way to see if array exists before I do a find?

DRYer way to see if array exists before I do a find?

Re: DRYer way to see if array exists before I do a find?

Re: DRYer way to see if array exists before I do a find?

Re: DRYer way to see if array exists before I do a find?

Re: DRYer way to see if array exists before I do a find?

Re: DRYer way to see if array exists before I do a find?

Re: DRYer way to see if array exists before I do a find?

Re: DRYer way to see if array exists before I do a find?

Re: DRYer way to see if array exists before I do a find?