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Scott Kulik

2008-Nov-07 04:01 UTC

creating empty array of items - should be a quick simple one

here is some of the code:

    @items_all = Item.find(:all)

    for item in @items_all do
      if not FileTest.exist?(item.image_name)
        @items_missing_images += item
      end
    end

You have a nil object when you didn''t expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.+

at @items_missing_images += item

so...how can i declare an empty array of Items?

i tried declaring @items_missing_images = []

but item is not of type array so this won''t work.
-- 
Posted via http://www.ruby-forum.com/.

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Chas Lemley

2008-Nov-07 04:06 UTC

head link

Re: creating empty array of items - should be a quick simple one

I''m new to this but could you do this:

above this put

@items_missing_images = Array.new

and then in your if statement do this

@items_missing_images << item

Chas

On Thu, Nov 6, 2008 at 11:01 PM, Scott Kulik <
rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
>
> here is some of the code:
>
>    @items_all = Item.find(:all)
>
>    for item in @items_all do
>      if not FileTest.exist?(item.image_name)
>        @items_missing_images += item
>      end
>    end
>
> You have a nil object when you didn''t expect it!
> You might have expected an instance of Array.
> The error occurred while evaluating nil.+
>
> at @items_missing_images += item
>
> so...how can i declare an empty array of Items?
>
> i tried declaring @items_missing_images = []
>
> but item is not of type array so this won''t work.
> --
> Posted via http://www.ruby-forum.com/.
>
> >
>
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Robert Zotter

2008-Nov-07 04:14 UTC

head link

Re: creating empty array of items - should be a quick simple one

Scott,

You need to declare the empty array first.
@items_missing_images = []

But do not use the ''@items_missing_images += item ''
Use @items_missing_images.push(item)
or    @items_missing_images << item

The += only works if you are adding an array to an array.

http://ruby-doc.org/core/classes/Array.html#M002232

Cheers

--
Robert Zotter
Zapient, LLC
Ruby on Rails Development and Consulting

http://www.zapient.com
http://www.fromjavatoruby.com

On Nov 6, 8:01 pm, Scott Kulik
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:> here is some of the code:
>
>     @items_all = Item.find(:all)
>
>     for item in @items_all do
>       if not FileTest.exist?(item.image_name)
>         @items_missing_images += item
>       end
>     end
>
> You have a nil object when you didn''t expect it!
> You might have expected an instance of Array.
> The error occurred while evaluating nil.+
>
> at @items_missing_images += item
>
> so...how can i declare an empty array of Items?
>
> i tried declaring @items_missing_images = []
>
> but item is not of type array so this won''t work.
> --
> Posted viahttp://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@googlegroups.com
For more options, visit this group at
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Robert Zotter

2008-Nov-07 04:18 UTC

head link

Re: creating empty array of items - should be a quick simple one

I probably should mention the best way to do what you are trying to
accomplish would be:

@items_missing_images = @items_all.reject { |item| FileTest.exist?
(item.image_name) }

--
Robert Zotter
Zapient, LLC
Ruby on Rails Development and Consulting

http://www.zapient.com
http://www.fromjavatoruby.com

On Nov 6, 8:14 pm, Robert Zotter
<rzot...-pPleKHUOxhtBDgjK7y7TUQ@public.gmane.org>
wrote:> Scott,
>
> You need to declare the empty array first.
> @items_missing_images = []
>
> But do not use the ''@items_missing_images += item ''
> Use @items_missing_images.push(item)
> or    @items_missing_images << item
>
> The += only works if you are adding an array to an array.
>
> http://ruby-doc.org/core/classes/Array.html#M002232
>
> Cheers
>
> --
> Robert Zotter
> Zapient, LLC
> Ruby on Rails Development and Consulting
>
> http://www.zapient.comhttp://www.fromjavatoruby.com
>
> On Nov 6, 8:01 pm, Scott Kulik
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
> wrote:
>
> > here is some of the code:
>
> >     @items_all = Item.find(:all)
>
> >     for item in @items_all do
> >       if not FileTest.exist?(item.image_name)
> >         @items_missing_images += item
> >       end
> >     end
>
> > You have a nil object when you didn''t expect it!
> > You might have expected an instance of Array.
> > The error occurred while evaluating nil.+
>
> > at @items_missing_images += item
>
> > so...how can i declare an empty array of Items?
>
> > i tried declaring @items_missing_images = []
>
> > but item is not of type array so this won''t work.
> > --
> > Posted viahttp://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
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rubyonrails-talk+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
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Scott Kulik

2008-Nov-07 04:27 UTC

head link

Re: creating empty array of items - should be a quick simple one

thanks for both replies!  that''s exactly what i was looking for.
-- 
Posted via http://www.ruby-forum.com/.

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Rails - Nov 2008 - creating empty array of items - should be a quick simple one

creating empty array of items - should be a quick simple one

Re: creating empty array of items - should be a quick simple one

Re: creating empty array of items - should be a quick simple one

Re: creating empty array of items - should be a quick simple one

Re: creating empty array of items - should be a quick simple one