ruby - 删除文件中的行 - Ruby

Question

在特定行中存在特定值的情况下，从 ruby​​ 中的 CSV 文件中删除行的巧妙方法是什么？

这是一个文件示例:

350 lbs., Outrigger Footprint, 61" x 53", Weight, 767 lbs., 300-2080
350 lbs., Outrigger Footprint, 61" x 53", Weight, 817 lbs., 300-2580
350 lbs., Outrigger Footprint, 61" x 53", Weight, 817 lbs., 300-2580
350 lbs., Outrigger Footprint, 69" x 61", Weight, 867 lbs., 300-3080
350 lbs., Outrigger Footprint, 69" x 61", Weight, 867 lbs., 300-3080

理想情况下，我想要一个只用这个创建的新文件:

350 lbs., Outrigger Footprint, 61" x 53", Weight, 767 lbs., 300-2080
350 lbs., Outrigger Footprint, 61" x 53", Weight, 817 lbs., 300-2580
350 lbs., Outrigger Footprint, 69" x 61", Weight, 867 lbs., 300-3080

当给出这个时:

300-2580
300-3080
300-2080

所以我知道我可以使用 sort filename|uniq -d 来做到这一点，但我正在尝试学习 Ruby(有点痛苦)。

提前致谢，中号

Answer 1

您可以使用它来获取 csv 文件中数组中的唯一行

File.readlines("file.csv").uniq
=> ["350 lbs., Outrigger Footprint, 61\" x 53\", Weight, 767 lbs., 300-2080\n", "350 lbs., Outrigger Footprint, 61\" x 53\", Weight, 817 lbs., 300-2580\n", "350 lbs., Outrigger Footprint, 69\" x 61\", Weight, 867 lbs., 300-3080\n"]

要将其写入新文件，您可以以写入模式打开文件，将其写入文件:

File.open("new_csv", "w+") { |file| file.puts File.readlines("csv").uniq }

要比较值，您可以使用 split在“,”上运行，像这样访问每一列:

rows = File.readlines("csv").map(&:chomp) # equivalent to File.readlines.map { |f| f.chomp }
mapped_columns = rows.map { |r| r.split(",").map(&:strip) }
=> [["350 lbs.", " Outrigger Footprint", " 61\" x 53\"", " Weight", " 767 lbs.", " 300-2080"], ["350 lbs.", " Outrigger Footprint", " 61\" x 53\"", " Weight", " 817 lbs.", " 300-2580"], .....]
mapped_columns[0][5]
=> "300-2080"

如果您想要更多功能，最好安装 FasterCSV gem .