如何在文本文件中找到一个表达式，并处理所有行，直到下一个表达式出现，并重复，直到文件结束

Question

我有一个文本文件:

Some comment on the 1st line of the file.
processing date:         31.8.2016
amount:                  -1.23
currency:                EUR
balance:                 1234.56
payer reference:         /VS123456/SS0011223344/KS1212
type of the transaction: Some type of the transaction 1
additional info:         Amount: 1.23 EUR 29.08.2016 Place: 123456789XY

processing date:         30.8.2016
amount:                  -2.23
currency:                EUR
balance:                 12345.56
payer reference:         /VS123456/SS0011223344/KS1212
type of the transaction: Some type of the transaction 2
additional info:         Amount: 2.23 EUR 28.08.2016 Place: 123456789XY

processing date:         29.8.2016
amount:                  -3.23
currency:                EUR
balance:                 123456.56
payer reference:         /VS123456/SS0011223344/KS1212
type of the transaction: Some type of the transaction 2
additional info:         Amount: 2.23 EUR 27.08.2016 Place: 123456789XY

我需要处理文件，所以我将有右边的值，31.8.2016, -1.23, EUR, 1234.56等，存储在MySQL数据库中。

我只实现返回包含特定字符串的行的1次出现或使用find或find_all的所有行，但这还不够，因为我需要以某种方式识别以"处理日期:"开始并以"附加信息:"结束的块，并处理那里的值，然后处理下一个块，下一个，直到文件结束。

有什么提示如何实现这一点吗?

Answer 1

我想从这个开始:

File.foreach('data.txt', "nn") do |li|
  next unless li[/^processing/]
  puts "'#{li.strip}'"
end

如果"data.txt"包含您的内容，foreach将读取该文件并返回li中的文本段落，而不是行。一旦你有了这些，你就可以随心所欲地操纵它们。这是非常快速和高效的，并且没有readlines或任何基于read的I/O可能存在的可伸缩性问题。

输出:

'processing date:         31.8.2016
amount:                  -1.23
currency:                EUR
balance:                 1234.56
payer reference:         /VS123456/SS0011223344/KS1212
type of the transaction: Some type of the transaction 1
additional info:         Amount: 1.23 EUR 29.08.2016 Place: 123456789XY'
'processing date:         30.8.2016
amount:                  -2.23
currency:                EUR
balance:                 12345.56
payer reference:         /VS123456/SS0011223344/KS1212
type of the transaction: Some type of the transaction 2
additional info:         Amount: 2.23 EUR 28.08.2016 Place: 123456789XY'
'processing date:         29.8.2016
amount:                  -3.23
currency:                EUR
balance:                 123456.56
payer reference:         /VS123456/SS0011223344/KS1212
type of the transaction: Some type of the transaction 2
additional info:         Amount: 2.23 EUR 27.08.2016 Place: 123456789XY'

你可以从包装'中看到，文件是按"nn"描述的块或段落读取的，然后每个块被剥离以去除尾随的空白。

参见foreach文档获取更多信息。

split(':', 2)是你的朋友:

'processing date:         31.8.2016'.split(':', 2) # => ["processing date", "         31.8.2016"]
'amount:                  -1.23'.split(':', 2) # => ["amount", "                  -1.23"]
'currency:                EUR'.split(':', 2) # => ["currency", "                EUR"]
'balance:                 1234.56'.split(':', 2) # => ["balance", "                 1234.56"]
'payer reference:         /VS123456/SS0011223344/KS1212'.split(':', 2) # => ["payer reference", "         /VS123456/SS0011223344/KS1212"]
'type of the transaction: Some type of the transaction 1'.split(':', 2) # => ["type of the transaction", " Some type of the transaction 1"]
'additional info:         Amount: 1.23 EUR 29.08.2016 Place: 123456789XY'.split(':', 2) # => ["additional info", "         Amount: 1.23 EUR 29.08.2016 Place: 123456789XY"]

你可以这样做:

text = 'processing date:         31.8.2016
amount:                  -1.23
currency:                EUR
balance:                 1234.56
payer reference:         /VS123456/SS0011223344/KS1212
type of the transaction: Some type of the transaction 1
additional info:         Amount: 1.23 EUR 29.08.2016 Place: 123456789XY'
text.lines.map{ |li| li.split(':', 2).map(&:strip) }.to_h
# => {"processing date"=>"31.8.2016", "amount"=>"-1.23", "currency"=>"EUR", "balance"=>"1234.56", "payer reference"=>"/VS123456/SS0011223344/KS1212", "type of the transaction"=>"Some type of the transaction 1", "additional info"=>"Amount: 1.23 EUR 29.08.2016 Place: 123456789XY"}

有许多方法可以继续将信息解析为更有用的数据，但这取决于您自己。