Ruby: Is there a better way to iterate over multiple (big) files?

Here's what I'm doing (sorry for the variable names, I'm not using those in my code):

File.open("out_file_1.txt", "w") do |out_1|
  File.open("out_file_2.txt", "w") do |out_2|
    File.open_and_process("in_file_1.txt", "r") do |in_1|
      File.open_and_process("in_file_2.txt", "r") do |in_2|
        while line_1 = in_1.gets do
          line_2 = in_2.gets        #input files have the same number of lines
          #process data and output to files
        end
      end
    end
  end
end

The open_and_process method is just to open the file and close it once it's done. It's taken from the pickaxe book.

Anyway, the main problem is 开发者_Go百科that the code is nested too deeply. I can't load all the files' contents into memory, so I have to iterate line by line. Is there a better way to do this? Or at least prettify it?

You don't need to use open's block syntax in cases where it makes no sense to do so

http://ruby-doc.org/core/classes/IO.html#M002239

I'm not sure that this version is all that much better for the two-file case, but it's certainly less deeply nested.

outfiles = [1,2].map {|n| File.open("outfile#{n}.txt", 'w') }
infiles =  [1,2].map {|n| File.open("infile#{n}.txt", "r")}
while (lines = infiles.map {|f| f.gets})).all?
  lines.each_with_index {|l, n| outfiles[n].puts("processed #{l}")}
end
(outfiles + infiles).each {|f| f.close}