From: Gary Wright <gwtmp01@...>
Date: 2007-03-31T05:15:16+09:00
Subject: Re: text processing


On Mar 30, 2007, at 3:31 PM, Stephen Smith wrote:
> line = ""
> record = ""
> oldLog = File.open("filename.txt")
> newLog = File.new("filename_formatted.csv", "w")
> hdr = "field1, field2, field3,...."
> newLog << hdr
> arr = oldLog.readlines
> arr.each do |line|
> record <<
> /(.{8})(.{6})(.{15})(.{3})(.{30})(.{4})(.{15})(.{1})(.{12})(. 
> {9})/.match(line).captures.join(',')
> << "\n"
> newLogg << record
> record = ""
> end

How about making it so you don't have to type that pattern next time:

def columns(*widths)
   Regexp.new(widths.map {|count| "(.{#{count}})" }.join)
end
pattern = columns(6,15,3,30,4,15,1,12,9)

You also can get rid of the intermediate strings and the potentially  
huge
internal array (from slurping up your oldLog into an array):

oldLog.each { |line|
   newLog.print pattern.match(line).captures.join(',')
}