Hi all,
What I am trying to do:
1) Search for books at a specific school
2) Iterate through each book and find all its related subbooks where
the book state is of a specific type
3) Return an array of those subbooks for each book
4) Since the array will have subarrays of the subbooks, flatten them
into one big array
5) then return the subbook with the lowest sequence number
What I did:
subbook = Subbook.get_for_assignment(site, :available_for_assignment)
def self.get_for_assignment(site,book_state)
books = Book.where(:location_id => site, :location_type =>
''Site'').all
available_books = books.each.map do |book|
book.subbooks.where(:book_state_id =>
BookState[:available_for_assignment].id)
end
raise ApplicationError, "Book out of order" unless
available_books.size > 0
available_book = available_books.flatten.map(&:sequence).min
#available_books.flatten.first (temporary although inaccurate fix)
if available_book.sequence > 100
available_book.book.update_attributes! :book_state_id =>
BookState[:distributed].id
end
available_book
end
The results:
"undefined method sequence for 1:Fixnum"
This line right here:
available_books.flatten.map(&:sequence).min
produces the above error. It''s this part
"map(&:sequence).min" that is
causing it. Basically I am flattening the array of subbooks and then
searching the one which has the lowest value for the sequence
attribute, corresponding to a sequence field in the subbooks table.
thanks for response
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On 28 June 2011 18:10, John Merlino <stoicism1-YDxpq3io04c@public.gmane.org> wrote:> available_books = books.each.map do |book| > book.subbooks.where(:book_state_id => > BookState[:available_for_assignment].id) > end > > available_books.flatten.map(&:sequence).min > > "undefined method sequence for 1:Fixnum" > > produces the above error. It''s this part "map(&:sequence).min" that is > causing it. Basically I am flattening the array of subbooks and then > searching the one which has the lowest value for the sequence > attribute, corresponding to a sequence field in the subbooks table.The problem is that the "array of subbooks" isn''t an array of subbooks, it''s an array of something which includes some integers. Hence, when you iterate it, you get an undefined method for Integer. I would be inspecting the available_books array in debug (or the console) and seeing what it really consists of. BTW, I''d also suggest that the whole "get_for_assignment" method could be achieved by a scope with the appropriate conditions... -- 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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
Thanks for response. I checked with logger and it is indeed an array:
logger.info "Is array? #{available_books.flatten.is_a?(Array)}"
#outputs: true
It''s an array of subbook objects:
<Subbook:0x10bef7de0>#<Subbook:0x10bef7ca0>#<Subbook:
0x10bef7bb0>#<Subbook:0x10bef7ae8>#<Subbook:0x10bec0ed0>#<Subbook:
0x10bec0db8>#<Subbook:0x10bec0cc8>#<Subbook:0x10bec0840>#<Subbook:
0x10bea9140>#<Subbook:0x10bea8fd8>#<Subbook:0x10bea8e70>#<Subbook:
0x10bea8c90>#<Subbook:0x10be8a998>#<Subbook:0x10be8a678>#<Subbook:
0x10be8a268>#<Subbook:0x10be86c80>#<Subbook:0x10be780e0>#<Subbook:
0x10be78018>#<Subbook:0x10be77f28>#<Subbook:0x10be77e88>#<Subbook:
0x10be69b58>#<Subbook:0x10be69ab8>#<Subbook:0x10be699a0>#<Subbook:
0x10be698d8>#<Subbook:0x10be63d98>#<Subbook:0x10be63cf8>#<Subbook:
0x10be63b90>#<Subbook:0x10be63af0>#<Subbook:0x10be5d3d0>#<Subbook:
0x10be5cd90>#<Subbook:0x10be5c4f8>#<Subbook:0x10be5c3e0>#<Subbook:
0x10be53768>#<Subbook:0x10be53420>#<Subbook:0x10be532e0>#<Subbook:
0x10be531f0>#<Subbook:0x10be46180>#<Subbook:0x10be45e88>#<Subbook:
0x10be45ac8>#<Subbook:0x10be45960>
Now when I look at above, it appears to reference the class itself,
and since Active Record converts fields to instance methods, the class
itself doesn''t have access to the sequence instance method, only
instances of the class.
Is this the problem and how would I address it?
Thanks for response
On Jun 28, 1:34 pm, Michael Pavling
<pavl...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> On 28 June 2011 18:10, John Merlino
<stoici...-YDxpq3io04c@public.gmane.org> wrote:
>
> > available_books = books.each.map do |book|
> > book.subbooks.where(:book_state_id =>
> > BookState[:available_for_assignment].id)
> > end
>
> > available_books.flatten.map(&:sequence).min
>
> > "undefined method sequence for 1:Fixnum"
>
> > produces the above error. It''s this part
"map(&:sequence).min" that is
> > causing it. Basically I am flattening the array of subbooks and then
> > searching the one which has the lowest value for the sequence
> > attribute, corresponding to a sequence field in the subbooks table.
>
> The problem is that the "array of subbooks" isn''t an
array of
> subbooks, it''s an array of something which includes some integers.
> Hence, when you iterate it, you get an undefined method for Integer.
>
> I would be inspecting the available_books array in debug (or the
> console) and seeing what it really consists of.
>
> BTW, I''d also suggest that the whole
"get_for_assignment" method could
> be achieved by a scope with the appropriate conditions...
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hmmm, this returns true as well:
logger.info "is true? #{available_books.flatten.first.respond_to?
(''sequence'')}"
On Jun 28, 3:22 pm, John Merlino <stoici...-YDxpq3io04c@public.gmane.org>
wrote:> Thanks for response. I checked with logger and it is indeed an array:
>
> logger.info "Is array? #{available_books.flatten.is_a?(Array)}"
> #outputs: true
>
> It''s an array of subbook objects:
> <Subbook:0x10bef7de0>#<Subbook:0x10bef7ca0>#<Subbook:
>
0x10bef7bb0>#<Subbook:0x10bef7ae8>#<Subbook:0x10bec0ed0>#<Subbook:
>
0x10bec0db8>#<Subbook:0x10bec0cc8>#<Subbook:0x10bec0840>#<Subbook:
>
0x10bea9140>#<Subbook:0x10bea8fd8>#<Subbook:0x10bea8e70>#<Subbook:
>
0x10bea8c90>#<Subbook:0x10be8a998>#<Subbook:0x10be8a678>#<Subbook:
>
0x10be8a268>#<Subbook:0x10be86c80>#<Subbook:0x10be780e0>#<Subbook:
>
0x10be78018>#<Subbook:0x10be77f28>#<Subbook:0x10be77e88>#<Subbook:
>
0x10be69b58>#<Subbook:0x10be69ab8>#<Subbook:0x10be699a0>#<Subbook:
>
0x10be698d8>#<Subbook:0x10be63d98>#<Subbook:0x10be63cf8>#<Subbook:
>
0x10be63b90>#<Subbook:0x10be63af0>#<Subbook:0x10be5d3d0>#<Subbook:
>
0x10be5cd90>#<Subbook:0x10be5c4f8>#<Subbook:0x10be5c3e0>#<Subbook:
>
0x10be53768>#<Subbook:0x10be53420>#<Subbook:0x10be532e0>#<Subbook:
>
0x10be531f0>#<Subbook:0x10be46180>#<Subbook:0x10be45e88>#<Subbook:
> 0x10be45ac8>#<Subbook:0x10be45960>
>
> Now when I look at above, it appears to reference the class itself,
> and since Active Record converts fields to instance methods, the class
> itself doesn''t have access to the sequence instance method, only
> instances of the class.
>
> Is this the problem and how would I address it?
>
> Thanks for response
>
> On Jun 28, 1:34 pm, Michael Pavling
<pavl...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
>
>
>
>
>
>
> > On 28 June 2011 18:10, John Merlino
<stoici...-YDxpq3io04c@public.gmane.org> wrote:
>
> > > available_books = books.each.map do |book|
> > > book.subbooks.where(:book_state_id =>
> > > BookState[:available_for_assignment].id)
> > > end
>
> > > available_books.flatten.map(&:sequence).min
>
> > > "undefined method sequence for 1:Fixnum"
>
> > > produces the above error. It''s this part
"map(&:sequence).min" that is
> > > causing it. Basically I am flattening the array of subbooks and
then
> > > searching the one which has the lowest value for the sequence
> > > attribute, corresponding to a sequence field in the subbooks
table.
>
> > The problem is that the "array of subbooks" isn''t
an array of
> > subbooks, it''s an array of something which includes some
integers.
> > Hence, when you iterate it, you get an undefined method for Integer.
>
> > I would be inspecting the available_books array in debug (or the
> > console) and seeing what it really consists of.
>
> > BTW, I''d also suggest that the whole
"get_for_assignment" method could
> > be achieved by a scope with the appropriate conditions...
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On Jun 28, 6:10 pm, John Merlino <stoici...-YDxpq3io04c@public.gmane.org> wrote:> This line right here: > > available_books.flatten.map(&:sequence).min > > produces the above error. It''s this part "map(&:sequence).min" that is > causing it. Basically I am flattening the array of subbooks and then > searching the one which has the lowest value for the sequence > attribute, corresponding to a sequence field in the subbooks table. >I suspect the error is actually being raised on the next line where you do available_book.sequence > 100 since you''ve set available_book to available_books.flatten.map(&:sequence).min, ie available_book is the smallest sequence number Fred> thanks for response-- 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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
actually you are right. my intention was to get the object with the smallest sequence number, not return the sequence number itself. The ruby documentation says this: "Returns the object in enum with the minimum value. " for min. Hence, I thought it would return the object.> I suspect the error is actually being raised on the next line where > you do > > available_book.sequence > 100 > > since you''ve set available_book > to available_books.flatten.map(&:sequence).min, ie available_book is > the smallest sequence number > > Fred > > > > > > > > > thanks for response-- 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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Jun 29, 12:04 am, John Merlino <stoici...-YDxpq3io04c@public.gmane.org> wrote:> actually you are right. my intention was to get the object with the > smallest sequence number, not return the sequence number itself. The > ruby documentation says this: "Returns the object in enum with the > minimum value. " for min. Hence, I thought it would return the object. > >It depends what you are iterating over - because you first called map(&:sequence) the enumerable in question was the array of sequence numbers. If you want to get back the object with the smallest sequence value you should drop the call to map and either use the block form of min or min_by Fred> > > I suspect the error is actually being raised on the next line where > > you do > > > available_book.sequence > 100 > > > since you''ve set available_book > > to available_books.flatten.map(&:sequence).min, ie available_book is > > the smallest sequence number > > > Fred > > > > thanks for response-- 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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
Good catch, Fred. On 29 June 2011 00:04, John Merlino <stoicism1-YDxpq3io04c@public.gmane.org> wrote:> actually you are right. my intention was to get the object with the > smallest sequence numberSo when you said in your first post: "This line right here ... produces the above error.", how had you determined it was that line? The error message would have told you *exactly* what line was causing a problem; did you check which line it was, or just assume? :-/ -- 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-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.