Rails 大CSV文件字段修改

https://dalibornasevic.com/posts/68-processing-large-csv-files-with-ruby

CSV.foreach 效率和占用内存方面都相对要好

# 修改原文件中Email列字段，并保存为新csv文件
write_parameters = { write_headers: true, headers: ["Id","Score","Text","Ip Address","Email","External Id","Response Date","Survey Source URL","Metric Type","Tags"] }

CSV.open('/tmp/new_export20190702-4-ng8cew.csv', 'w+', write_parameters) do  |new_csv|

  CSV.foreach('/tmp/export20190702-4-ng8cew.csv', headers: true) do  |row|

    puts  "#{row['Id']}---#{row['Email']}"

    user_email = User.find_by(email: row['Email'])&.effective_email 
    row['Email'] = user_email || row['Email']
    new_csv << row
  end
end