Question

刚刚进入Ruby,我正试图学习一些基本的读物指挥,而我已经找到任何可靠的来源。

我试图从档案中穿过某些线,直到档案结束。

So in the file where it says FILE_SOURCES I want to read all the sources til end of file, and place them in a file.

我发现,整个档案都印刷,替换档案中的文字,但我想读到档案中的某些部分。

Answer 1

我想这样做(假设你可以把整个档案读到记忆中):

source_lines = IO.readlines( source_file.txt )
start_line   = source_lines.index{ |line| line =~ /SOURCE_LINE/ } + 1
File.open(  other_file.txt ,  w  ) do |f|
  f << source_lines[ start_line..-1 ].join( "
" )
end

相关方法:

IO.readlines to read the lines into an array
Array#index to find the index of the first line matching a regular expression
File.open to create a new file on disk (and automatically close it when done)
Array#[] to get the subset of lines from the index to the end

如果你能够把全部档案读到记忆中,那么我对“tadman”基于国家的语种作更简单的改动:

started = false
File.open(  other_file.txt ,  w  ) do |output|
  IO.foreach(  source_file.txt  ) do |line|
    if started then
      output << line
    elsif line =~ /FILE_SOURCES/
      started = true
    end
  end
end

Answer 2

通常,如果你试图从一个限定一些how的档案中提取一个小节的话,你会照此办理:

open(filename) do |f|
  state = nil

  while (line = f.gets)
    case (state)
    when nil
      # Look for the line beginning with "FILE_SOURCES"
      if (line.match(/^FILE_SOURCES/))
        state = :sources
      end
    when :sources
      # Stop printing if you hit something starting with "END"
      if (line.match(/^END/))
        state = nil
      else
        print line
      end
    end
  end
end

你可以根据你所复阅的部分档案,从一个州向另一个州转变。

Answer 3

File.open("file_to_read.txt", "r") {|f|
  line = f.gets
  until line.include?("FILE_SOURCES")
    line = f.gets
  end
  File.open("file_to_write.txt", "w") {|new_file|
    f.each_line {|line|
      new_file.puts(line) 
    }
   new_file.close
  }
  f.close 
}

Answer 4

IO的职能没有概念档案中的“线”是什么。没有任何直截了当的方法在档案中渗入某一条线,你不得不阅读,无视你不需要的路线。

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