Rails csv row from parent record with many child associations

Question

I have a members table from which I pull:member_id, :client_uid, :first_name, and:last_name. The Members table has a has_many association to Quality Measures from which I pull:measure and:measure_status for each association and flatten it.

I am trying to get the desired Members data and the flattened Quality Measure data into one CSV row.

Since there can be any number of Quality Measure associated records, I get the max number of associated records and create that number of Measure and Measure Status columns and create the proper number of headers:

max_qm_associations = get_max_qm_associations(filtered_members_ids)

    column_headers = ["Member ID", "Client UID","First Name", "Last Name"]

    max_qm_associations.times do |qm|
      column_headers += ["Measure", "Measure Status"]
    end

so that the desired output appears like the following assuming the max number of Quality Measure associated records for my Members is 2. Therefore:

Member ID	Client UID	First Name	Last Name	Measure	Measure Status	Measure	Measure Status
1	23232	John	Doe	Drink Coffee	Met	Eat	Not Met
2	32323	Jane	Doe	Walk	Met	none	none

So far I've tried many things. My most recent looks nice enough (but not the goal) by putting the Measure - Measure Status in the first Measure column:

csv = CSV.generate(headers: true) do |csv|
      # Add headers
      csv << column_headers

      filtered_members.each do |member|
        # Add member data
        qm_measures = ""
        member.quality_measures.each do |qm|
          qm_measures << [qm.measure, qm.measure_status.upcase].join(' - ') + "\n"
        end

        csv << [member.id, member.client_uid, member.first_name.humanize, member.last_name.humanize, qm_measures]

      end
    end

The result:

Member ID	Client UID	First Name	Last Name	Measure	Measure Status	Measure	Measure Status
1	23232	John	Doe	Drink Coffee - Met \n Eat - Not Met
2	32323	Jane	Doe	Walk - Met \n

Another attempt simply did the above but only as comma separated array values:

csv = CSV.generate(headers: true) do |csv|
      # Add headers
      csv << column_headers

      filtered_members.each do |member|
        # Add member data
        csv << [member.id, member.client_uid, member.first_name.humanize, member.last_name.humanize, member.quality_measures.map {|qm| "#{qm.measure}, #{qm.measure_status}"}.flatten]

      end
    end

This result:

Member ID	Client UID	First Name	Last Name	Measure	Measure Status	Measure	Measure Status
1	23232	John	Doe	"Drink Coffee,Met", "Eat,Not Met"
2	32323	Jane	Doe	"Walk,Met"

Again, as a refresher, my desired output is as follows:

Member ID	Client UID	First Name	Last Name	Measure	Measure Status	Measure	Measure Status
1	23232	John	Doe	Drink Coffee	Met	Eat	Not Met
2	32323	Jane	Doe	Walk	Met	none	none

Edits: Table formats keep breaking on submit.

Answer 1

The problem seems to come from this part member.quality_measures.map {|qm| "#{qm.measure}, #{qm.measure_status}"}.flatten member.quality_measures.map {|qm| "#{qm.measure}, #{qm.measure_status}"}.flatten it returns you the following array ["Drink Coffee,Met", "Eat,Not Met"] You would probably want to do this in your code:

member.quality_measures.map{|qm| "#{qm.measure}", "#{qm.measure_status}"}.flatten

that will return the ["Drink Coffee","Met", "Eat","Not Met"] and then you would possibly want to flatten the whole array that you append like so:

csv << [member.id, member.client_uid, member.first_name.humanize, member.last_name.humanize, member.quality_measures.map {|qm| "#{qm.measure}", "#{qm.measure_status}"}.flatten].flatten

I did not test it yet but it should work if you go in that direction.

Answer 2

Thanks to @iseitz!

I was only one.flatten away from my desired output.

csv = CSV.generate(headers: true) do |csv|
      # Add headers
      csv << column_headers

      filtered_members.each do |member|
        qms = member.quality_measures.map {|qm| ["#{qm.measure}", "#{qm.measure_status}"]}.flatten
        csv << [member.id, member.client_uid, member.first_name.humanize, member.last_name.humanize, qms].flatten
      end
    end