In Ruby- Parsing Directory and reading first row of the file

Question

Below is the piece of code that is supposed read the directory and for each file entry prints the first row of the file. The issue is x is not visible so file is not being parsed.

Dir.foreach("C:/fileload/src") do |file_name|
  x = file_name
  puts x
  f = File.open("C:/fileload/src/" +x)
  f.readlines[1..1].each do |line| 
    puts line 
  end
end

Answer 1

Why are you assigning x to file_name? You can use file_name directly. And if you are only reading the first line of the file, why not try this?

#!/usr/bin/ruby

dir = "C:/fileload/src"
Dir.foreach(dir) do |file_name|
    full = File.join(dir, file_name)
    if File.file?(full)
        f = File.open(full)
        puts f.first
        f.close
    end
end

You should use File.join to safely combine paths in Ruby. I also checked that you are opening a file using the File.file? method.

Answer 2

You have no visibility issue with x. You should be using File::join or Pathname#+ to build your file paths. You should exclude non-files from consideration. You're selecting the second line, not the first with [1..1]. Here's a cleaner correct replacement for your sample code.

dir = "C:/fileload/src"
Dir.foreach(dir).
map    { |fn| File.join(dir,fn) }.
select { |fn| File.file?(fn) }.
each   { |fn| puts File.readlines(fn).first }