Question

I’m having issues with this regex it doesn’t seem to grab the titles (everything after the last ‘.’ ) I’ve tested the regex on multiple sources and they all seem to grab the correct grouping. Is it something with the scan function that I am doing wrong?

##### data.csv file #####
## Web_Sites.Shopping.Newegg,...
## Web_Sites.Shopping.Newegg_Secure,...
## Web_Sites.Shopping.O'Reilly_Books,...
## Web_Sites.Shopping.PackageTrackr,...
#####

## Grab the title from the list
regex = '([\w_-]+)$'

## Open the CSV File
data_file = CSV.open("data.csv", "r")

## Set the file we will append the data.
my_file = File.new("titles.csv", 'a')

## For each line in the data file, get the correct title
data_file.each do |data|
   note = data[0]
   title = note.scan(regex)
   my_file.print "#{note} : #{title}"
end

Thank you,
LF4

Answer 1

You’re not giving scan a regular expression argument, you’re giving it a plain string and the string '([\w_-]+)$' probably doesn’t appear anywhere in your note so scan doesn’t do anything useful. You want to use the Regexp class to create and store your regular expression:

regex = Regexp.new('([\w_-]+)$')

Or (thankyou Kudo) you could use one of the regex literal forms:

regex = /([\w_-]+)$/
regex = %r{([\w_-]+)$}

And then pass that instance of Rexexp to note.scan:

note.scan(regex)