From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2011-06-14T02:43:18+09:00
Subject: Re: Regexp.match(line) question

On Mon, Jun 13, 2011 at 7:32 PM, m b <snert@hotmail.se> wrote:
>
> Hi,
> I new to Ruby.  It's a lot of fun to learn..
>
> if I do this:
>
> f=open('filename.dat','r')
> str=f.read
>
> and then:
>
> str.each_line  do |line|
>    /ruby/.match(line)
>
> ruby prints out variable line and say its a RegexpError
> 'empty range in character class'  as if it interprets  line as a Regexp
> What am I doing wrong?  There are a lot of strange characters in variable line,
> maybe that is the issue?

I'm not sure about the issue, but the usual idiom for this is:

File.foreach("filename.dat") do |line|
  line.match(/ruby/)
end

This way:
- The file handler is automatically closed for you, you don't have to
ensure that you call close on it, it's done for you.
- You only have one line at a time in memory, since that seems to be
your unit of data. If the file is huge it will make a difference in
the amount of memory you will consume at a time.

In any case, String#match calls Regexp#match, so calling match on one
or the other should make no difference. Can you show a small example
of a file that breaks?

Jesus.