From: dblack@...
Date: 2003-08-01T21:54:51+09:00
Subject: Re: A bundle of newbie queries

Hi --

On Fri, 1 Aug 2003, Brian Candler wrote:

> On Fri, Aug 01, 2003 at 09:30:19PM +0900, dblack@superlink.net wrote:
> > If you just want the count of lines with plastic_1.1..., you could do:
> >
> >   plastic_count = file.readlines.grep(/plastic_1.1.../).size
> >
> > or, to save reading the whole file in at once:
> >
> >   plastic_count = 0
> >   file.readlines.each do |line|
> >     plastic_count += 1 if /plastic_1.1.../.match(line)
> >   end
>
> That example also reads in the entire file: that's what 'readlines' does :-)
>
> But File is an Enumerable object. Hence you can do
>
>     plastic_count = file.grep(/plastic_1.1.../).size
>
> (which will generating an intermediate array of matching lines only), or
>
>     plastic_count = 0
>     file.each do |line|
>       plastic_count += 1 if /plastic_1.1.../.match(line)
>     end
>
> (which generates no intermediate array at all)

Yikes.  I seem to have readlines disease.  Thanks for the corrections.


David

-- 
David Alan Black
home: dblack@superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav