From: Chad Perrin <code@...>
Date: 2011-07-15T09:54:48+09:00
Subject: Re: Is there a more efficient way to remove data from a string?

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On Fri, Jul 15, 2011 at 09:37:14AM +0900, Eddie Catflap wrote:
> Hi
>=20
> I have a regex as follows
>=20
> REG1=3DRegexp.new=3D('dodgydata')
>=20
> Basically, I need to read a file in line by line, and on each line
> that's a match for my regex, remove everything from the point of the
> regex to the end of that line. Is there a more efficient way to do it
> than what I have at the moment? I have some HUGE files to process, and
> many more regex matches to capture.. :-/

I'd probably do it something like this:

    ARGF.each_line do |line|
      line.sub!(/#{reg1}.*/, '')
      puts line
    end

=2E . . unless I could be sure the end of the regex in reg1 included .*
after the match you want to find, in which case the second line of that
would look more like this:

      line.sub!(reg1, '')

This, of course, assumes that reg1 actually contains a regex object.  If
it contains a string, go back to my first example, because strings don't
deal well with regex special characters.


>=20
> (As you can see I'm no ruby expert!).

We all start somewhere.  I wouldn't exactly call myself an "expert"
either.


>
> I'd like to be able to make this more efficient, just doesn't seem a
> very Ruby way to do things.. All help gratefully accepted!

Note: I have not tested for execution time of my solution.  I just wrote
it off the top of my head to conform to my sense of good, clean Ruby
code.

--=20
Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ]

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