[plug] [Perl] sorign arrays based on scalar value

[Anthony J. Breeds-Taurima]

On Fri, 15 Nov 2002, Patrick Tehvand wrote:

> 'ello all,
> I sent this to the SLPWA list by mistake...
> 
> I've got another perl question,
> I would like to sort in decending nemerical order based on $id
> This is what I have.
> 
> sub resort() {
>    #Sort everthing out into numerical order
>    my @final;
>    my $inputfile=$_[0];
>    open (THING,"<$inputfile");
>    my @sortinput=<THING>;
>    close THING;
>       for $input(@sortinput) {
>       chop ($input);
>       ($id,$title,$words)=split(/\|/,$input);
> 
>       @final = ____some sorting stuff___
> 
>       open (RESORT,">$inputfile");
>       for $line(@final) {
> 	print RESORT "$line";
>       }
>       close RESORT;
>       return 0;
> }
> }

use a Hash;
sub resort($$) {
	my $inputfile = shift;               #Get function args.
	my $outputfile = shift;

	#pre-decalre vars.
	my %allData;

	#Open the input file
	open(IN, "<$inputfile") or die;
	while(<IN>) {
		# extract data into individual vars and store in a hash.
		chop;
		my ($id,$title,$words)=split(/\|/,$input);

		$allData{$id}{title}=$title;		
		$allData{$id}{words}=$words;		
	}
	close(IN);

	open(OUT,">$outputfile") or die;

	#reverse sort by id [I'm assuming it's numeric] and output.
	foreach my $id (sort {$b <=> $a} keys %allData) {
		print join('|',$id,$allData{$id}{title},$allData{$id}{words}),
		      "\n";
	}
	close(OUT);
	retirn 0;
}

It's not the only way to do it, and if your dat set is large then there are
better ways but, this should demo the perl sort function.

#include <http://thor.cantech.net.au/~tony/stddisclaimer.h>

Yours Tony

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