在 ruby 中访问实例变量

Question

我正在尝试运行 ruby 下面的代码。我得到@selectcells 的零值。有什么建议么？

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

当我如下所示添加 ap @selectcells 时，我得到了一个有效值。看来我无法从外部访问实例变量@selectcells 的值。

    @selectcells=@selectnodes1.num_rows
    ap @selectcells

Answer 1

将 getter 添加到 class 以使其可访问。它毕竟是一个实例变量，而您正试图将它当作一个全局变量来获取：

def selectsells
  @selectsells
end
# or: attr_reader :selectsells

并通过以下方式访问：

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

在 ruby 中访问实例变量

Access Instance variable in ruby

ruby

instance-variables