For counting average

Rails
1

I am passing hard time with ruby on rails …I was trying to count the
average of a whole table…at first I calculated avarage of eah
column
then average of the average values but it is giving me an error- here
are
my codes and error-
error-

NoMethodError in Rate_schools#index

Showing /home/vmuser/workspace/project3
-3/app/views/rate_schools/index.html.erb where line #36 raised:

undefined method `+’ for nil:NilClass

Extracted source (around line #36):

33:
34:
35:
36: Average
<%=((@avg1+@avg2+@avg3+@avg4+@avg5+@avg6+@avg7+@avg8)/8)%>
37: <% end %>
38:
39:

codes In controller:
def index

    @school=School.find(params[:id])
      @rate_school [email protected]_schools.build


 @[email protected]_schools.average(:library)

@[email protected]_schools.average(:careercenter)
@[email protected]_schools.average(:location)
@[email protected]_schools.average(:food)
@[email protected]_schools.average(:healthcenter)
@[email protected]_schools.average(:studentactivities)
@[email protected]_schools.average(:facilities)
@[email protected]_schools.average(:internetspeed)

codes in index :
<% if !@school.rate_schools.blank? %>

library=<%=@avg1%> careercenter=<%=@avg2%> location=<%=@avg3%> Food=<%=@avg4%> Healthcenter=<%=@avg5%> studentactivities=<%=@avg6%> facilities=<%=@avg7%> internetspeed=<%=@avg8%> 
      Average

<%=((@avg1+@avg2+@avg3+@avg4+@avg5+@avg6+@avg7+@avg8)/8)%>
<% end %>

      </tr>
        </table>
2

You should have a nil value to any @avg, try to use

@avgN = @school.rate_schools.average(:X) || 0

2012/5/20 Roy [email protected]

39:
@[email protected]_schools.average(:library)

–
Fernando A.

3

On Sun, May 20, 2012 at 10:09 AM, Fernando A. <
[email protected]> wrote:

You should have a nil value to any @avg, try to use

@avgN = @school.rate_schools.average(:X) || 0

I also suggest to pass all of that logic to the model so after finding
the
school:
in controller
@school = School.find(params[:id])
@avg1 = @school.food_average

in model
def food_average
rate_school.average(:food)
end

4

Thanks a lot…it’s working…great group!

On Sun, May 20, 2012 at 11:09 AM, Fernando A. <