From: "Mark J. Reed" <markjreed@...>
Date: 2003-09-17T09:12:56+09:00
Subject: Re: scrambler one-liner

On Tue, Sep 16, 2003 at 05:04:48PM -0700, Sabby and Tabby wrote:
> Xavier Noria <fxn@hashref.com> wrote:
> 
> > -pe 'gsub!(/\w+/){|w|r=1..w.size-2;w[r]=w[r].split(//).sort_by{rand}.to_s;w}'
> 
>   -pe 'gsub!(/\B\w+\B/){|w|w.split(//).sort_by{rand}}'
> 
> In Perl, the criosomapn fnutcoin uesd by srot() is rreqeuid to behave
> cisnotsltney, so tihs seohtrr one-lenir may not be ksoher:
> 
>   -pe 's!\B\w+\B!join"",sort{.5>rand}$&=~/./g!ge'

Right.  That's also true of the block passed to Ruby's Array#sort
method.  The one-liner users Array#sort_by, whose block is used to
assign a key to each array element.  It's basically a shortcut for
a Schwartzian transform:

	x = y.sort_by { |i| z(i) }

is roughly equivalent to this Perl code:

	$x =  map  { $_->[1] } 
	      sort { $a->[0] <=> $b->[0] } 
  	      map  { [z($_), $_] } 
	      @y

-Mark