From: "gigaday@..." <gigaday@...>
Date: 2006-11-13T19:35:06+09:00
Subject: beginner's question about passing arrays as arguments to methods

I am doing a little script that builds an array (called darray) of all
filenames in a directory tree.  I am doing this by recursively calling
a method (called enter_dir) and passing the partially filled array
(called darray) down through the recursive calls.

The code works, but I am concerned about the efficiency of passing what
is potentially quite a large array around so many times.  Should I be
concerned about this or not?

I also wrote the code using a global array ($darray) and this worked
too and didn't need to array to be passed down through the recursions.

What are the pros and cons of these two approaches?


def enter_dir(this_dir, darray)
farray = []
this_dir.each {|fname|
  farray << fname
  }
farray.each {|fname|
  file_path = this_dir.path + '/' + fname
  if File.stat(file_path).directory?
    this_dir_sub = Dir.new(file_path)
    if fname != '.' && fname != '..'
      enter_dir(this_dir_sub, darray)
    end
  else
    darray << file_path
  end
}
end

this_dir = Dir.new('/home/tony/Ruby/dot_recycle')
darray = []
enter_dir(this_dir, darray)
puts darray