Re: arbitrary sort

[Shawn H Corey]

On Tue, 25 Mar 2014 09:55:25 -0400
shawn wilson <ag4ve...@gmail.com> wrote:

> i want to sort an array for certain key words first and then
> alphabetically.
> 
> my @foo = qw/foo bar baz first second third/;
> 
> foreach my $i (sort {$a cmp $b} @foo) {
>   print "$i\n";
> }
> 
> How do I make 'first', 'second', and 'third' come before the rest?
> (I'm actually dealing with a hash)
> 

Try:

my @foo = qw/foo bar baz first second third/;
my @preferences = qw( first second third );

my %preferences;
{
  my $i = 1;
  %preferences = map { $_ => $i++ } @preferences;
  $preferences{''} = $i;
}

my @sorted_foo = map { $_->[0] }
                 sort { $a->[1] <=> $b->[1]
                      || $a->[0] cmp $b->[0]
                      }
                 map { [ $_, $preferences{$_} || $preferences{''} ] }
                 @foo;

print "Unsorted:  @foo\n";
print "Sorted:    @sorted_foo\n";


-- 
Don't stop where the ink does.
        Shawn

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