From: Mike Stok <mike@...>
Date: 2006-09-15T09:15:43+09:00
Subject: Re: Newbie regexp question


On 14-Sep-06, at 7:37 PM, James Calivar wrote:

> Hello,
>
> I'm trying to split a formatted text file into four separate columns.
> The data is comprised of lines of text that are bundled into four
> distinct columns, corresponding to a "Required versus Optional"
> variable, a requirement number, a requirement classification  
> (R1=Rev 1,
> F=Future, I=Internal), and a textual description of the requirement.
>
> My raw data looks like this in the input text file:
>
> R [01]	R1	The system shall support "emergency call processing"
> R [02]	R1	The system shall support "local call processing"
> R [08]	F	The system shall provide a command-line user interface
> R [723]	F	The system shall provide 6 10/100/1000 Ethernet interfaces
> R [11]	F	The system shall support VoIP networks
> R [398]	R1	The system shall contain 2 control boards
> O [327]	I	The system should support hotswapping of all internal boards
> R [19]	I	The system shall be able to detect transmission errors
> R [631]	F	The system shall continue processing data as long as a  
> call is
> active.
>
> I've set up a loop to process each line in the input file, and what  
> I'd
> like to get is four separate variables containing on a line-by-line
> basis the data corresponding to the four distinct columns.  The  
> problem
> is my regexp experience is next to nothing, and I can't figure out how
> to extract the data I want since my fourth column contains whitespace
> (I'd have used that as my column separator otherwise).
>
> Here's my loop:
>
> File.open(textfile, "r") do |input_file|
>   while line = input_file.gets
>       output_file << line
>   end
> end
>
> What can I replace the simple copy statement (output_file << line)  
> with
> in order to get what I want?
>
> Thanks in advance, I hope this question makes some sense.

You have a number of options - if your data is tab delimited (i.e.  
the first "two" coluumns are really one):

s = 'R [01]	R1	The system shall support "emergency call processing"'
p s.split(/\t/)

=> ["R [01]", "R1", "The system shall support \"emergency call  
processing\""]

or you can just split on whitespace and specify a limit on the number  
of fields:

s = 'R [01]	R1	The system shall support "emergency call processing"'
p s.split(/\s+/, 4)

=> ["R", "[01]", "R1", "The system shall support \"emergency call  
processing\""]

Or you can use a regex (ick ;-)

Hope this helps,

Mike




-- 

Mike Stok <mike@stok.ca>
http://www.stok.ca/~mike/

The "`Stok' disclaimers" apply.