From: Robert Klemme <bob.news@...>
Date: 2005-05-02T16:24:25+09:00
Subject: Re: Newbie Question About files


"Jeff Singer" <jsinger@freshlooktech.com> schrieb im Newsbeitrag
news:4274E508.5020002@freshlooktech.com...
> I am still fairly new to ruby, and have been working on a fairly small
> project.
> Ive looked through the online book on ruby central, Why's Poignant
> guide, and the ruby-doc documentation on both File and IO, but I still
> can't get the program to work.
> Im trying ouput an array containing binary data to a file, the code is:
>
> 176: filename = gets
> 177: aFile = File.new(filename, 'w')
> 178: @file.each {|element| aFile.print element}
> 179:  aFile.close
>
> @file is an array of bytes, broken into blocks of 500 that Id like to
> send to the file that Im prompted for.
> And those numbers aren't actually there, as they are the line numbers.
>
> The error I get no matter how I format the name of the file is:
> project.rb:177:in `initialize': Invalid argument -
> *whatever_I_just_typed*  (Errno::EINVAL)
>
> Does anyone have any Ideas/suggestions on how to get this to work.

Additional notes to make your code a bit safer:

 - use binary output, regardless of OS, for documentation and portability

 - use the block form of File.open, for exception safety

 - use write instead of print, to avoid any interpretation of the data to
print

So, assuming that @file contains an array of strings with maxlen 500
(these hold the binary data I assume),  that would make:

filename = gets.chomp
File.open( filename, 'wb' ) do |aFile|
  @file.each {|data| aFile.write data}
end

You can even make it a 1-liner:

File.open( gets.chomp, 'wb' ) {|aFile| @file.each {|data| aFile.write
data} }

:-)

Kind regards

    robert