删除文件中的行 - Ruby [英] remove rows in file - Ruby
问题描述
这是一个文件的示例:
这是一个聪明的方法来从一个特定值存在于特定行的ruby中的CSV文件中删除行? / p>
350磅,支腿脚印,61x 53,重量,767磅,300-2080
350磅,脚趾脚印,61x 53,重量,817磅,300-2580
350磅,支腿脚印,61x 53,重量,817磅,300-2580
350磅,舷外脚印,69x 61,重量,867磅,300-3080
350磅,舷外脚印,69x 61,重量,867磅,300-3080
理想情况下,我只想创建一个新文件:
350磅,支腿脚印,61x 53,重量,767磅,300-2080
350磅,支腿脚印,61 x 53,重量,817磅,300-2580
350磅,舷外脚印,69x 61,重量,867磅,300-3080
给予这个:
300-2580
300-3080
300- 2080
所以我知道我可以用 sort filename | uniq -d
但我正在尝试学习Ruby(有点痛苦)。
提前感谢
M
你可以使用它来获取csv文件中的数组中的唯一行。
File.readlines(file.csv)。 uniq
=> [350磅,支腿脚印,61,53,重量,767磅,300-2080,350磅,舷外脚印,61 \x 53 ,重量,817磅,300-2580 \,350磅,支腿脚印,69 \x 61 \,重量,867磅,300-3080 \
要将其写入新文件,可以在写入模式下打开文件,将其写入文件: / p>
File.open(new_csv,w +){| file | file.puts File.readlines(csv)。uniq}
为了比较值,您可以使用拆分功能,,以访问每一列,如下所示:
rows = File.readlines(csv)。map(&:chomp)#等效于File.readlines.map {| f | f.chomp}
mapped_columns = rows.map {| r | r.split(,)。map(&:strip)}
=> [[350磅,舷外脚印,61,53,重量,767磅,300-2080),[350磅舷外脚印,61 \x 53 \,重量,817磅,300-2580],.....]
mapped_columns [0] [5]
=> 300-2080
如果你想要更多的功能,你最好安装 FasterCSV宝石。
What is a clever way to remove rows from a CSV file in ruby where a particular value exists in a particular row?
Here's an example of a file:
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
Ideally, I'd want a new file created with only this:
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
when given this:
300-2580
300-3080
300-2080
so I know i can do this with sort filename|uniq -d
but I'm trying to learn Ruby (somewhat painfully).
Thanks in advance, M
You can use this to get the unique lines in an array in a csv file
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"]
To write it to a new file, you can open a file in write mode, write this into the file:
File.open("new_csv", "w+") { |file| file.puts File.readlines("csv").uniq }
For comparing values, you can use split function on ",", to access each column like this:
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"
If you want more functionality, you are better off installing FasterCSV gem.
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