Reading values into an array

Question

I'm trying to read some values into an array in an .each do code block the simplest way possible but I'm having issues. I'm importing a csv file via a rake file I built, which will update a table with new rows, thus creating new id's. I'm trying to take each id that is created and save them into an array. And I'm wanting to be able to access the values stored in that array in another rake task.

The following code is for the rake file that will import the csv file and whose newly generated id's I wish to capture in an array. It currently does what it's supposed to do but you can only import one new row at a time.

Import_incidents_csv.rake

require 'csv'

namespace :import_incidents_csv do

task :create_incidents => :environment do
    puts "Import Incidents"

    csv_text = File.read('c:/rails/thumb/costrecovery_csv/lib/csv_import/incidents.csv')
    csv = CSV.parse(csv_text, :headers => true)
    csv.each do |row|
        row = row.to_hash.with_indifferent_access
        Incident.create!(row.to_hash.symbolize_keys)
    end

    @last_incident_id = Incident.last.id

    end
  end

This is another rake file that imports another csv file that I need to have the values stored in the array assigned to. And again, currently it works fine if you just import one new row, but if you import multiple rows then everything goes a little haywire.

Import_timesheets_csv.rake

require 'csv'

namespace :import_timesheets_csv do

 task :create_timesheets => :environment do
    puts "Import Timesheets"

    csv_text = File.read('c:/rails/thumb/costrecovery_csv/lib/csv_import/timesheets.csv')
    csv = CSV.parse(csv_text, :headers => true)
    csv.each do |row|
        row = row.to_hash.with_indifferent_access
        Timesheet.create!(row.to_hash.symbolize_keys)
    end

    timesheet = Timesheet.last
    timesheet.incident_id = @last_incident_id
    timesheet.save

    @last_timesheet_id = Timesheet.last.id

     end
end

I read this resource for dealing with arrays http://www.tutorialspoint.com/ruby/ruby_arrays.htm and it seems very confusing. Here is my best guess of what the Import_incidents_csv.rake file might look like with reading values into an array. And I have the puts at the end so I can verify that the integers are properly getting stored in the array. Once I get everything working, I'll remove it.

require 'csv'

def inc_id
@inc_id = Incident.last.id
end

namespace :import_incidents_csv do

 task :create_incidents => :environment do
    puts "Import Incidents"

    csv_text = File.read('c:/rails/thumb/costrecovery_csv/lib/csv_import/incidents.csv')
    csv = CSV.parse(csv_text, :headers => true)
    csv.each do |row|
        row = row.to_hash.with_indifferent_access
        Incident.create!(row.to_hash.symbolize_keys)
        Incident.last.id = @inc_id
        id_array = Array.new(@inc_id)
    end

    puts "#{id_array}"

      end
  end

tadman · Accepted Answer · 2012-09-27 14:26:27Z

2

I'm not sure what you're trying to do here, your question is far from clear, but it might be that you're trying to collect the id values of the inserted records into an array:

id_array = [ ]

csv.each do |row|
  incident = Incident.create!(row.to_hash.symbolize_keys)
  id_array << incident.id
end

Once this has finished, id_array will have all of the created record id values in it. As a note, if any of these create! calls fails you will get an ActiveRecord::RecordInvalid exception which you will need to rescue somehow and handle. As such, it makes sense to wrap this entire operation inside of Indcident.transaction do ... end to ensure the whole thing can be rolled back if one fails, presuming your database supports transactions. If you don't care about failures, you may call create instead which will not throw exceptions.

There's a lot of redundancy in your example there which has been omitted. Calling Array.new is hardly ever required as, like JavaScript, you can declare a new array with [ ] either empty or pre-populated with something like [ 1 ] or [ 1, 2 ].

answered Sep 27, 2012 at 14:26

tadman

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2 Comments

RubyDude1012 Over a year ago

You answered my question perfectly, thanks. Ive got the incident ids being stored in a gloabal array that I can access in another rake file. So now how do I empty the contents of that array into a column called incident_id until the array is empty. Here's a guess: Timesheet.create!(row.to_hash.symbolize_keys) (newline) timesheet = Timesheet.last (newline) timesheet.incident_id << @id_array

tadman Over a year ago

I'm not sure what you're intending with timesheet.incident_id << @id_array since you probably mean to reverse those. << is used to add things to an array in the form of array << item. As with UNIX shell redirection, think of the angle brackets as funnels, where you're funnelling things into the array.

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