I've written some code to sort an array by the values in another array. I'd like some monastery reaction, pointers, and correction.

Precisely what I want to do, is sort the elements of an array, @sortme = qw(foo bar baz cat dog elephant bird, based on the order of the elements in another array, @order = (whale elephant dog cat), placing unlisted (in @order) items at the end of the list.

Here's the code: 

#!/usr/bin/perl -w

use strict;
use Data::Dumper;


my @sites = qw(Hillsboro Rialto Santa_Ana Memphis Richmond);

my @sortme = sort {$a cmp $b} @sites;
unshift @sortme, 'Foo', 'Bar';


print Dumper \@sortme;

{    my %order;
    foreach (0..$#sites)
    {    $order{$sites[$_]} = $_;  # build index
    }
    $order{DEFAULT} = $#sites + 1;
    
my @sorted = sort    {    if (exists $order{$a} && exists $order{$b})
                        {    $order{$a} <=> $order{$b}
                        } elsif  ( exists $order{$a})
                        {    $order{$a} <=> $order{DEFAULT}
                        } elsif ( exists $order{$b} )
                        {    $order{DEFAULT} <=> $order{$b}
                        } else
                        {    $a cmp $b }
                    } @sortme;

print Dumper \@sorted
}

[download]
This seems to work fine. But, I'd like to know, is there a better/faster/cleaner algorithm that I would know of if I didn't always sleep through my CS classes? Should I be using map to do this?

TIA


TGI says moo

In reply to Sorting an array by another array by TGI

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