Output array to CSV in Ruby

To a file:

require 'csv'CSV.open("myfile.csv", "w") do |csv|  csv << ["row", "of", "CSV", "data"]  csv << ["another", "row"]  # ...end

To a string:

require 'csv'csv_string = CSV.generate do |csv|  csv << ["row", "of", "CSV", "data"]  csv << ["another", "row"]  # ...end

Here's the current documentation on CSV: http://ruby-doc.org/stdlib/libdoc/csv/rdoc/index.html

If you have an array of arrays of data:

rows = [["a1", "a2", "a3"],["b1", "b2", "b3", "b4"], ["c1", "c2", "c3"]]

Then you can write this to a file with the following, which I think is much simpler:

require "csv"File.write("ss.csv", rows.map(&:to_csv).join)

I've got this down to just one line.

rows = [['a1', 'a2', 'a3'],['b1', 'b2', 'b3', 'b4'], ['c1', 'c2', 'c3'], ... ]csv_str = rows.inject([]) { |csv, row|  csv << CSV.generate_line(row) }.join("")#=> "a1,a2,a3\nb1,b2,b3\nc1,c2,c3\n" 

Do all of the above and save to a csv, in one line.

File.open("ss.csv", "w") {|f| f.write(rows.inject([]) { |csv, row|  csv << CSV.generate_line(row) }.join(""))}

NOTE:

To convert an active record database to csv would be something like this I think

CSV.open(fn, 'w') do |csv|  csv << Model.column_names  Model.where(query).each do |m|    csv << m.attributes.values  endend

Hmm @tamouse, that gist is somewhat confusing to me without reading the csv source, but generically, assuming each hash in your array has the same number of k/v pairs & that the keys are always the same, in the same order (i.e. if your data is structured), this should do the deed:

rowid = 0CSV.open(fn, 'w') do |csv|  hsh_ary.each do |hsh|    rowid += 1    if rowid == 1      csv << hsh.keys# adding header row (column labels)    else      csv << hsh.values    end# of if/else inside hsh  end# of hsh's (rows)end# of csv open

If your data isn't structured this obviously won't work