[Cialug] Algorithm; Cutting Up A File

[David W. Body]

Ruby (in a Perlish style):

#!/usr/bin/env ruby
in_file = ARGV[0]
File.read(in_file).scan(/<(.*)>(.*)<\/\1>/m).each do |match|
    out_file = in_file.gsub(/\./, "-#{match[0]}.")
   File.open(out_file, "w") {|f| f.print match[1].strip }
end

;-)
--David

On Dec 12, 2006, at 4:52 PM, Todd Walton wrote:

> Hey scripters,
>
> I'm having trouble concocting an algorithm to cut up a text file into
> blocks.  I'm going to have text files that have three distinct blocks
> of information in them, and each block will be marked in some way.  By
> HTML style tags, I suppose.  For example:
>
> ~/filez> cat datafile.txt
> <description>
> This is a data file.  It holds data.
> </description>
>
> <procedure>
> 1. Read the file.
> 2. Ponder meaning of existence.
> 3. Write new file.
> </procedure>
>
> <reference>
> /usr/dict/datafile
> </reference>
>
> ~/filez> _
>
> What I can assume about these files is that each will have three
> pre-defined blocks of text, enclosed by HTML style tags.  The tags are
> on their own line.  There may or may not be text outside of these
> three blocks.  There may or may not be blank lines between the blocks.
> The blocks may or may not be in a given order.  Etc.
>
> How can I read in the file's contents, take out the text between the
> tags (but not the tags!), and write that text to a file?  I begin with
> datafile.txt, I run the script, and I end up with
> datafile-description.txt, datafile-procedure.txt, and
> datafile-reference.txt.  Here's what I have so far:
>
> while datafile.position != end
>       # The block for description.
>       strLine = datafile.readNextLine
>       if strLine contains "<description>" then
>               until strLine = "</description>"
>                       strLine = datafile.readNextLine
>                       write strLine to datafile-description.txt
>               end until
>       end if
>
>       # The block for procedure. (same as for description)
>       # The block for reference. (same as for description)
> end while
>
> So, the script runs through the text file line by line, until it finds
> the opening description tag and then, starting with the next line,
> writes it all out to a new file until it comes to the end-description
> tag.  Same for the other two.  Will this work?  If the blocks are out
> of order in the datafile will this still work?  Should I change
> something?
>
> -todd
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