Rob Dixon wrote:
>
> Wesley Phillips wrote:
> > Hi all,
> > I have been working on a problem and worked out a solution, but am
> > wondering if there is an easier(more elegant?) way of doing it. I am
> > automatically generating configuration files for a Quality Of Service(QOS)
> > device, and each pipe in the QOS has a policy number attached to it. The
> > policy numbers must be unique, so I have to find an unused number. The
> > system never has more than 200 or so policies. I am pulling the preexisting
> > policy numbers out of a database and placing them into an array(@addarr)
> > Here is my code:
> >
> >
> > #!/usr/bin/perl
> >
> > use Mysql;
> >
> > $db = Mysql->connect('localhost', 'dbase', 'user', 'password');
> > $query = $db->query("SELECT policy FROM Table");
> > while ( $policy = $query->fetchrow_array()) {
> > $addarr[$policy] = $policy;
> > }
> > for ($i = 1; $i < 1001; $i++) {
> > if (defined($addarr[$i])) {
> > next;
> > } else {
> > $newaddr = $i;
> > last;
> > }
> > }
> >
> > where $newaddr would be the new, as yet unused, number
>
> Hi Wes.
>
> First of all,
>
> use strict; # always
> use warnings # usually
>
> Secondly the Mysql module is now deprecated in favour of DBI together with
> its DBD::mysql driver.
>
> However I can well believe that either or both of these points are dictated
> by your employer, so here's the answer...
>
> It looks like you want the smallest number in 1 .. 1000 which doesn't already
> exist in the 'policy' column of 'Table'. What I'd do is to start by setting
> up a hash with all of the valid values as keys. Then simply drag in all of
> the current values of this column into an array and use it to delete the
> corresponding elements of the hash. The number you want is then the first
> of the sorted list of remaining hash keys. It looks like this:
>
> use strict;
> use warnings;
>
> use Mysql;
>
> my $db = Mysql->connect('localhost', 'dbase', 'user', 'password');
>
> # Set up the hash with 1000 elements
> #
> my %policy;
> @policy{1 .. 1000} = ();
>
> # Delete all those currently in use
> #
> my @current = $db->query("SELECT policy FROM Table")->fetchcol;
> delete @[EMAIL PROTECTED];
>
> # The next one to use is the first of those left
> #
> my $next = (sort keys %policy)[0];
You are sorting numbers so you should use a numerical sort otherwise
'20' will be sorted after '100' etc.
my $next = (sort { $a <=> $b } keys %policy)[0];
Or you could use an array:
my @policy = 0 .. 1000;
delete @policy[ @current ];
my $next;
$next = $_ and last for @policy;
John
--
use Perl;
program
fulfillment
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