[perl-win32-gui-users] RE: Right way to sort(WAS Schwartzian Transform?) < Look Ma, an intelligible and descriptive subject line.....

[Frazier, J. J. <Joe...@Pe...>]

> -----Original Message-----
> From: $Bill Luebkert [mailto:db...@wg...]
> Sent: Wednesday, September 05, 2001 22:47
> To: Frazier, Joe Jr
> Cc: per...@li...
> Subject: Re: Schwartzian Transform?
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> "Frazier, Joe Jr" wrote:

> >         I have the above data structure( which will=20
> ultimatly contain
> > 6-7 items per array reference and many array elements) and=20
> need to be
> > able to sort/reverse sort on any of the reference elements.=20
>  I know the
> > Schwartzian Transform is the right way to go, but I havent=20
> a clue how to
> > start(tried a few things, but no luck).  Example:

<cut attempt=3D"totallywrong" code=3D"bad" />

> >         Please help.  Forgive the HTML post, I have to=20
> access my work
> > email from home using Outlook web mail access.....
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> You don't need it here.
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> use strict;
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> my @rows =3D (
>   ['Joe', 'Frazier, Jr.', ''],=20
>   ['abracadabra', 'magic word', ''],=20
>   ['John', 'First name', ''],=20
>   ['ciao', 'greetings', 'five'],=20
> );
> my @result;
>         =20
> dosort (\@rows, \@result, 1, 'f');
> exit 0;
>         =20
> sub dosort {		# dosort \@sort, \@result, column 0 to=20
> n, 'f'|'r'
> 	my ($sort, $sorted, $col, $dir) =3D @_;
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> if ($dir eq 'f') {
> 	@$sorted =3D sort { $a->[$col] cmp $b->[$col] } @$sort;
> } else {
> 	@$sorted =3D sort { $b->[$col] cmp $a->[$col] } @$sort;
> }
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> }
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> __END__=20


Thanks Bill, that did EXACTLY what I needed!  Here is part of the script
I have been working (Win32::GUI::Listview control) in case anyone else
wants to look at it:

use Win32::GUI;
# define GLOBAL sort criteria:
my $dir =3D 'f';
my $sortCol;
# One thing not here is that I define a property of the lvwJobposts
object ($win->lvwJobposts->{Columns}) to hold the number(actually, the
last column index) of columns  in the list view.

....# create window and controls......

# given a listview control Named lvwJobposts:
sub lvwJobposts_ColumnClick{
	my $sort =3D shift;			# selected Column
	my @Rows;
	for(my $x =3D 0; $x < $win->lvwJobposts->Count();$x++){
		my @Values;
		for(my $y =3D 0; $y <=3D $win->lvwJobposts->{Columns};
$y++){
			my %data =3D $win->lvwJobposts->ItemInfo($x, $y);
			push @Values, $data{-text};	# push each
row->Column value into array
		}
		push @Rows, \@Values;  # push each row into @Rows array
	}
	if ($sort =3D=3D $sortCol){ 	# Determine if we are sorting on
same column as last time
		if($dir eq 'f'){		# if so, reverse sort
order....
			$dir =3D 'b';
		}elsif($dir eq 'b'){
			$dir =3D 'f';
		}	=09
	}else{					# otherwise, this is a
new column and set sort to forward
		$sortCol =3D $sort;
		$dir =3D "f";
	}
	my @result;
	dosort (\@Rows, \@result, $sort, $dir);
	$win->lvwJobposts->Clear();		# Clears the list view
	for (my $d =3D 0; $d <=3D $#result;$d++){
		Win32::GUI::DoEvents();			# thrown in in
case there a a large number of Rows
		$win->lvwJobposts->InsertItem(-text =3D>$result[$d]); #
adds back a row at a time
	}
}
sub dosort {		# dosort \@sort, \@result, column 0 to n,
'f'|'r'
	my ($sort, $sorted, $col, $dir) =3D @_;
	if ($dir eq 'f') {
		@$sorted =3D sort { $a->[$col] <=3D> $b->[$col] ||
$a->[$col] cmp $b->[$col] } @$sort;
	} else {
		@$sorted =3D sort { $b->[$col] <=3D> $a->[$col] ||
$b->[$col] cmp $a->[$col] } @$sort;
	}
}
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> PS:  Done much boxing lately ?  :)
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Not lately.  To busy trying to master Perl( it would help if I had a job
where it was what I did)

Now, anyone want to give me 1-2 examples of using the Schwartzian
Transform and break it down?( I have seen the one linked to from
perl.com, but it kind of makes my head hurt. I also searched google, but
found that one and a few other links that did not really explain when to
use and how it works.)

Joe Frazier, Jr
Technical Support Engineer
PeopleClick
919-645-2916
joe...@pe...
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