ruby在行首匹配字符串或空格/制表符，并将uniq行插入文件

Question

This is my code:

    File.open(file_name) do |file|
      file.each_line do |line|;
        if line =~ (/SAPK/) || (line =~ /^\t/ and tabs == true) || (line =~ /^ / and spaces == true)
        file = File.open("./1.log", "a"); puts "found a line #{line}"; file.write("#{line}".lstrip!)
        end
      end
    end

File.open("./2.log", "a") { |file| file.puts File.readlines("./1.log").uniq }

1. I want to to insert all the lines that match a specific string, start with tab or start with space to a file 1.log , all lines should be with space/tab at the beginning so I removed them.

2. I want get the unique lines in 1.log and write them to 2.log

3. It will be great if some can go over the code and tell me if something is not correct.

4. When using files in Ruby, what is the difference between the w+ and a modes?

I know:

w+ - Create an empty file for both reading and writing.

a - Append to a file.The file is created if it does not exist.

But both options append to the file, I though w+ should behave like > , instead of >> ,so I guess w+ also like >> ?

Thanks !!

Answer 1

There's a lot of confusion in this code and it isn't helped by your habit of jamming things on a single line for no reason. Do try and keep your code clean, as the functionality should be obvious. There's also a lot of quirky anti-patterns like stringifying strings and testing booleans vs booleans which you should really avoid doing.

One thing you'll want to do is employ Tempfile for those situations where you need an intermediate file.

Here's a reworked version that's cleaned up:

Tempfile.open do |temp|
  File.open(file_name) do |input|
    input.each_line do |line|
      if line.match(/SAPK/) || (line.match(/^\t/) and tabs) || (line.match(/^ /) and spaces)
        puts "found a line #{line}"

        temp.write(line.lstrip!)
      end
    end
  end

  File.open("./2.log", "w+") do |file|
    # Rewind the temporary file to read data back
    temp.rewind

    file.write(temp.readlines.uniq)
  end
end

Now a and w+ are largely similar, it's just two ways that are offered for people familiar with whatever notation. It's like how Array has both length and size which do the same thing. Pick one and use it consistently or your code will be confusing.

My criticism over things like x == true is because something that narrowly specific usually means that x could take on a multitude of values and true is one particular case we're trying to handle, something that implies that we should be aware it might be false and many other things. It's a red herring and will only invite questions.