Access Instance variable in ruby

Question

I am trying to run the code below in ruby. I am getting a nil value for @selectcells. Any suggestions?

class Neighbor_finder


@@path = "/home/xyz"

def initialize(enodebid,earfcn_dl,distance,spread,mcc,mnc)
@site_details=Hash.new
@radius = distance
@earfcn_dl=earfcn_dl
@spread=spread
@sourceenb=enodebid 
@plmn=mcc+mnc 
@mcc=mcc
@mnc=mnc
puts "here"
end

def enodeb_cell_finder
    enodebid=@sourceenb
    earfcn_dl=@earfcn_dl
    con=Mysql.new 'localhost','root','root','celldb'
    puts "here11"
    @site_details=con.query "SELECT * FROM enodeb WHERE enodeb_id LIKE '%#{enodebid}%'"

    u = @site_details.fetch_hash
    ap u
    con.close

   @con1 = Mysql.new 'localhost','root','root','celldb' 
    @selectnodes1 = @con1.query "SELECT * FROM cell_db_eutran_cells WHERE sitename LIKE  '%#{enodebid}%' AND earfcn_dl LIKE '#{earfcn_dl}'"

    @selectcells=@selectnodes1.num_rows


    end
 end


d=Neighbor_finder.new("936144","2581",20,60,'311','850').enodeb_cell_finder

ap @selectcells

---

When I add an ap @selectcells as shown below I do got a valid value. It just appears I can't access value of the instance variable @selectcells from outside.

    @selectcells=@selectnodes1.num_rows
    ap @selectcells

Answer 1

Add a getter to the class to make it accessible. It is an instance variable after all, and you are trying to get it as if it were a global one:

def selectsells
  @selectsells
end
# or: attr_reader :selectsells

And access it via:

d = Neighbor_finder.new("936144","2581",20,60,'311','850')
ap d.enodeb_cell_finder
ap d.selectsells