I was doing this:
@line_items = LineItems.find_all_by_invoice_id(params[:id])
@payments = Payments.find_all_by_invoice_id(params[:id])
@total = @line_items.sum{ |item| item.cost }
@payment_total = @payments.sum{ |payment| payment.value }
@balance = @total - @payment_total
But when no payments had been made it was coming up with an error when
trying to sum nil, so I did this:
begin
@payment_total = @payments.sum{ |payment| payment.value }
rescue
@payment_total = 0
end
So, when the sum failed it returned @payment_total as zero. Now, SURELY,
there''s a better way to do this? I''m sure it''s
obvious when you know
how. Please, enlighten me.
--
Posted via http://www.ruby-forum.com/.
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All you need to do to your original code is add a condition to make
sure @payments is not null:
@payment_total = @payments.sum{ |payment| payment.value } unless
@payments.nil?
Or can payment.value be nil for some payments but not others? Inject
could help in that case:
@payment_totals = @payments.inject(0) { |sum, p| sum + p.value unless
p.value.nil? }
Before running either one of these, you can initialize both @total and
@payment_total to zero:
@total, @payment_total = 0, 0
Hope that helps.
PS: Wonder if you need all of these to be @instance_variables ?
On Apr 1, 10:16 am, Tom Harvey
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:> I was doing this:
>
> @line_items = LineItems.find_all_by_invoice_id(params[:id])
> @payments = Payments.find_all_by_invoice_id(params[:id])
>
> @total = @line_items.sum{ |item| item.cost }
> @payment_total = @payments.sum{ |payment| payment.value }
>
> @balance = @total - @payment_total
>
> But when no payments had been made it was coming up with an error when
> trying to sum nil, so I did this:
>
> begin
> @payment_total = @payments.sum{ |payment| payment.value }
> rescue
> @payment_total = 0
> end
>
> So, when the sum failed it returned @payment_total as zero. Now, SURELY,
> there''s a better way to do this? I''m sure it''s
obvious when you know
> how. Please, enlighten me.
> --
> Posted viahttp://www.ruby-forum.com/.
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On Wed, Apr 1, 2009 at 9:16 AM, Tom Harvey <rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:> > I was doing this: > > @line_items = LineItems.find_all_by_invoice_id(params[:id]) > @payments = Payments.find_all_by_invoice_id(params[:id]) > > @total = @line_items.sum{ |item| item.cost } > @payment_total = @payments.sum{ |payment| payment.value }You can do @payment_total = @payments.sum{ |payment| payment.value } if @payments or @payment_total = @payments.sum{ |payment| payment.value } rescue 0 or @payment_total = @payments ? @payments.sum{ |payment| payment.value } : 0> @balance = @total - @payment_total > > > But when no payments had been made it was coming up with an error when > trying to sum nil, so I did this: > > begin > @payment_total = @payments.sum{ |payment| payment.value } > rescue > @payment_total = 0 > end > > So, when the sum failed it returned @payment_total as zero. Now, SURELY, > there''s a better way to do this? I''m sure it''s obvious when you know > how. Please, enlighten me.-- Greg Donald http://destiney.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 http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Thanks Guys, that''s much more Ruby like code! -- 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 -~----------~----~----~----~------~----~------~--~---