From: Robert Klemme <shortcutter@...>
Date: 2012-01-24T21:27:28+09:00
Subject: Re: Dynamically creating variables

On Tue, Jan 24, 2012 at 12:13 PM, Tris Hoar <trishoar@bgfl.org> wrote:
> I'm trying to write a script for an SNMP poller but I'm getting stuck trying
> to work out how to create my variables. The script will be processing a CSV
> of unknown length. It might be just 2 servers or it could be up to 20. I
> cant work out how I can find the list of servers from the CSV and then
> create variables for each one that I can keep track off through out the
> programs life to out put what I want.

You do not want to create variables.  Instead, you use collections.
With a Hash you can pick an appropriate key (e.g. IP or domain name of
server).  Yo could also store values in Hashes.

Example

13:25:53 Temp$ ruby19 csv.rb
{"172.16.0.1"=>
  {"host"=>"172.16.0.1",
   "port"=>"161",
   "community"=>"Public",
   "cluster"=>"Library",
   "shortName"=>"mwg1",
   "type"=>"mwg7",
   "rpsTotal"=>"0",
   "clientTotal"=>"0",
   "serverTotal"=>"0"},
 "172.16.0.2"=>
  {"host"=>"172.16.0.2",
   "port"=>"161",
   "community"=>"Public",
   "cluster"=>"Library",
   "shortName"=>"mwg2",
   "type"=>"mwg7",
   "rpsTotal"=>"0",
   "clientTotal"=>"0",
   "serverTotal"=>"0"}}
13:26:12 Temp$ cat dat.csv
host,port,community,cluster,shortName,type,rpsTotal,clientTotal,serverTotal
172.16.0.1,161,Public,Library,mwg1,mwg7,0,0,0
172.16.0.2,161,Public,Library,mwg2,mwg7,0,0,0
13:26:27 Temp$ cat -n csv.rb
     1  require 'csv'
     2  require 'pp'
     3
     4  head = nil
     5  data = {}
     6
     7  CSV.foreach("dat.csv") do |row|
     8    if head
     9      tmp = {}
    10
    11      head.zip row do |h,v|
    12        tmp[h] = v
    13      end
    14
    15      data[row.first] = tmp
    16    else
    17      head = row.each &:freeze
    18    end
    19  end
    20
    21  pp data
13:26:34 Temp$

Kind regards

robert


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