Pretty file size in Ruby?

Question

I\'m trying to make a method that converts an integer that represents bytes to a string with a \'prettied up\' format.

Here\'s my half-working attempt:

Answer 1

I agree with @David that it's probably best to use an existing solution, but to answer your question about what you're doing wrong:

1. The primary error is dividing s by self rather than the other way around.
2. You really want to divide by the previous s, so divide s by 1024.
3. Doing integer arithmetic will give you confusing results, so convert to float.
4. Perhaps round the answer.

So:

class Integer
  def to_filesize
    {
      'B'  => 1024,
      'KB' => 1024 * 1024,
      'MB' => 1024 * 1024 * 1024,
      'GB' => 1024 * 1024 * 1024 * 1024,
      'TB' => 1024 * 1024 * 1024 * 1024 * 1024
    }.each_pair { |e, s| return "#{(self.to_f / (s / 1024)).round(2)}#{e}" if self < s }
  end
end

lets you:

1.to_filesize
# => "1.0B"
1020.to_filesize
# => "1020.0B" 
1024.to_filesize
# => "1.0KB" 
1048576.to_filesize
# => "1.0MB"

Again, I don't recommend actually doing that, but it seems worth correcting the bugs.