Ruby CSV - 获取当前行/行号 [英] Ruby CSV - get current line/row number

问题描述

我试图找出如何从Ruby CSV获取当前行/行号。这是我的代码：

I'm trying to work out how to get the current line/row number from Ruby CSV. This is my code:

options = {:encoding => 'UTF-8', :skip_blanks => true}
CSV.foreach("data.csv", options, ) do |row, i|
   puts i
end

但这似乎没有按预期工作。有没有办法做这个？

But this doesn't seem to work as expected. Is there a way to do this?

推荐答案

Ruby有一个变量变量 $。 ，这是要读取的当前文件的行号：

Ruby has a magic variable $. which is the line number of the current file being read:

require 'csv'

CSV.foreach('test.csv') do |csv|
  puts $.
end

如果我读：

Year,Make,Model,Description,Price
1997,Ford,E350,"ac, abs, moon",3000.00
1999,Chevy,"Venture ""Extended Edition""","",4900.00
1999,Chevy,"Venture ""Extended Edition, Very Large""","",5000.00
1996,Jeep,Grand Cherokee,"MUST SELL!\nair, moon roof, loaded",4799.00

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$。始终在Perl中使用。在Ruby中，建议我们使用以下方式避免它的神奇一面：

$. is used all the time in Perl. In Ruby, it's recommended we use it the following way to avoid the "magical" side of it:

require 'english'

puts $INPUT_LINE_NUMBER

---

如果需要处理字段中嵌入的行末尾，则很容易通过小修改来处理。假设有一个CSV文件test.csv，其中包含一行带有嵌入的新行：

---

If it's necessary to deal with embedded line-ends in fields, it's easily handled by a minor modification. Assuming a CSV file "test.csv" which contains a line with an embedded new-line:

Year,Make,Model,Description,Price
1997,Ford,E350,"ac, abs, moon",3000.00
1999,Chevy,"Venture ""Extended Edition""","",4900.00
1996,Jeep,Grand Cherokee,"MUST SELL!
air, moon roof, loaded",4799.00
1999,Chevy,"Venture ""Extended Edition, Very Large""","",5000.00

使用枚举器的 with_index（1） 可以很容易地跟踪CSV对块产生的次数，使用 $。，但是在读取处理行末尾所需的额外行时尊重CSV的工作：

Using Enumerator's with_index(1) makes it easy to keep track of the number of times CSV yields to the block, effectively simulating using $. but honoring CSV's work when reading the extra lines necessary to deal with the line-ends:

require 'csv'

CSV.foreach('test.csv', headers: true).with_index(1) do |row, ln|
  puts '%-3d %-5s %-26s %s' % [ln, *row.values_at('Make', 'Model', 'Description')]
end

运行时输出：

$ ruby test.rb
1   Ford  E350                       ac, abs, moon
2   Chevy Venture "Extended Edition"
3   Jeep  Grand Cherokee             MUST SELL!
air, moon roof, loaded
4   Chevy Venture "Extended Edition, Very Large"

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