From: Nicholas Van Weerdenburg <vanweerd@...>
Date: 2005-01-13T01:24:48+09:00
Subject: Re: Comparing two files for equality

end is the end of an expression that returns an array.

# this is quivalent.
a=files.map do |file|
...
end
a.uniq

# Since everything in ruby is an expression, you can do:
files.map do |file|
...
end.uniq

# making the expression explicit...
(files.map do |file|
....
end).uniq

Regards,
Nick

On Thu, 13 Jan 2005 01:15:25 +0900, Andreas Semt <as@computer-leipzig.de> wrote:
> Florian Gross wrote:
> >
> > def files_equal?(*files)
> >   files.map do |file|
> >     File.size file
> >   end.uniq.size <= 1 and
> >   files.map do |file|
> >     File.read file
> >   end.uniq.size <= 1
> > end
> >
> 
> Could anybody please explain the "end.uniq.size" line?
> Thanks!
> 
> Greetings,
> Andreas
> 
> > This ought to be slightly faster in the average case.
> >
> > Other optimizations would be reading the files line-wise in parallel and
> > bailing out as soon as one of the lines differs.
> >
> 
> 


-- 
Nicholas Van Weerdenburg