为什么我的 CSV 在每一行之后写一个标题？

Question

我有一个名为 info 的数组，我想将每一行添加到 CSV，但我还想在文件顶部包含标题。

我这样做了：

  info.each do |listing|
    CSV.open(csvfile, "a+", write_headers: true, headers: ["Company_Name","Website","Street_Address", "City", "State", "Zip", "Phone","Email"]) do |csv|
      csv << listing
    end
  end

但这会产生如下所示的内容：

这不是我想要的。

我只想要顶部的 1 个标题行。

我如何做到这一点？

编辑 1

我实际上有另一个嵌套循环也有同样的问题，但我不能简单地将它移出循环 - 那我还能如何解决这个问题？

  csvs.each do |csv|
    CSV.foreach(csv, headers: true) do |row|
      #check for presence of valid email
      if (!row['Email'].nil?) && (!row['Email'].include? "no email")
        CSV.open(new_csv, "a+", write_headers: true, headers: ["Company_Name","Website","Street_Address", "City", "State", "Zip", "Phone","Email"]) do |new_csv_row|
          new_csv_row << row
          puts "#{row['Email']} successfully added to #{new_csv}"
        end
      end
    end
  end

Answer 1

对于第一个更改循环：

CSV.open(csvfile, "a+", write_headers: true, headers: ["Company_Name","Website","Street_Address", "City", "State", "Zip", "Phone","Email"]) do |csv|
  info.each do |listing|
    csv << listing
  end
end

第二个：

header_written = {} # memorize if header is allready written
csvs.each do |csv|
  ...
  # alternative can be 'write_headers: !File.exist?(new_csv)'
  # but this works only when this file is created here and no empty file exists
  CSV.open(new_csv, "a+", write_headers: !header_written[new_csv], headers: ["Company_Name","Website","Street_Address", "City", "State", "Zip", "Phone","Email"]) do |new_csv_row|
          new_csv_row << row
          puts "#{row['Email']} successfully added to #{new_csv}"
  end
  header_written[new_csv] ||= true

编辑：我刚才确实认识到new_csv 不是动态的。因此，您可以将第二个 CSV.open 调用也放在循环之外，或者使用简单的标志而不是 header_written[]，这样您就可以将其更改为 header_written = false|true。