Re: Shortening a script, but aiming for efficiency

On Fri, 2004-10-01 at 05:12, John W. Krahn wrote:
> Jose Alves de Castro wrote:
> > To make it short: I have a small filter that I'd like to keep as compact
> >  as possible, while not losing efficiency.
> > 
> > How it works:
> > 
> > 1) ignore the first line (it's a header line)
> > 2) if a line ends in a tab, remove that character
> > 3) replace all tabs with pipes
> > 4) if the line now ends in a pipe, add a space at the end
> > 
> > This all looks pretty easy, right?
> 
> Change that to three steps:
> 
> 1) ignore the first line (it's a header line)
> 2) replace all tabs with pipes
> 3) if a line ends in a pipe, change it to a space.

Well... all lines have fields separated with tabs and they all end in a
 tab, too...

Here are some examples:

a\tb\t
a\t\t
\tb\t
\t\t\t

The output for all these should be:

a|b
a|\s
 |b
 |\s

(I know \s isn't a space, but that was for stating it visually)

This means that I could start by replacing all tabs with pipes, but then
 I would always have to remove the last pipe...

I could replace two ending pipes with "| " (second and fourth cases),
 but I would also have to remove a single ending pipe (first and third
 cases)

Sorry if I wasn't clear in the beginning.


> Even easier.
> 
> 
> > So, here's an attempt:
> > 
> > #!/usr/bin/perl -lwn
> > use strict;
> > 
> > $. - 1 || next;
> > s/\t$//;
> > y/\t/|/;
> > s/\|$/ /;
> > print;
> 
> #!/usr/bin/perl -lwp
> use strict;
> 
> $. - 1 || next;
> y/\t/|/;
> s/\|$/ /;
> 
> 
> 
> John
-- 
José Alves de Castro <[email protected]>
  http://natura.di.uminho.pt/~jac