From: Robert Klemme <bob.news@...>
Date: 2005-04-18T19:39:32+09:00
Subject: Re: Modifying content in a file


"Ghislain Mary" <nospam@lunacymaze.org> schrieb im Newsbeitrag
news:4263856D.3050008@lunacymaze.org...
> Hi all,
>
> I've written a little code that replaces some content in a file, but I
> really think there is a better way to do so. Here's my code:
>
> def clean_file(filename)
>    # Define the new caption
>    caption = "caption: new caption"
>
>    # Process the content of the file
>    File.open(filename) do |from_file|
>      File.open(filename + ".new", 'w') do |to_file|
>        from_file.each do |line|
>          case
>            when line =~ /^caption:.*$/: line.sub!($&, caption)
>          end
>          to_file.print line

You can do that easier:

to_file.puts( /^caption:/ =~ line ? caption : line )

>        end
>      end
>    end
>
>    # Rename the file
>    File.delete(filename)
>    File.rename(filename + ".new", filename)
> end
>
> Can't it be done using the read-write mode on the file? Any better
> proposition is welcome ;)

Depends on your file's sizes.  If they are moderately sized you can slurp
the whole thing in, modify contents in mem with a single gsub and then
write them in one go.

Regards

    robert