in reply to search an array

If you're going to be looking up spids frequently, then yes, you may want to use a hash. Something like the following (untested) code is what you want: 
my $xpid = 1234;
%procs = map {$_ => 0} @{$dbh->selectall_arrayref(
                         "select spid from v\$process")};
if (defined($procs{$xpid})) {
   print "Pid is in use : $xpid\n";
}

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--roboticus

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Re^2: search an array
by jwkrahn (Abbot) on May 26, 2006 at 11:34 UTC
    You are assigning the value 0 to every key so every key will be defined however you can't test for truth because 0 is false. If instead of assigning 0 you assigned any non-zero value you wouldn't have to use defined() to test the keys: 
    my $xpid = 1234;

%procs = map { $_ => 1 } @{ $dbh->selectall_arrayref( "select spid fro
+m v\$process" ) };

if ( $procs{ $xpid } ) {
   print "Pid is in use : $xpid\n";
}

    [download]
    Another way to do it: 
    my $xpid = 1234;

@procs{ @{ $dbh->selectall_arrayref( "select spid from v\$process" ) }
+ } = ();

if ( exists $procs{ $xpid } ) {
   print "Pid is in use : $xpid\n";
}

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      jwkrahn:

      Thanks, I hadn't thought of that. It certainly simplifies things a bit!

      I'm not a perl golfer yet, but I think you just got a birdie! 8^)

      --roboticus

[reply]
      Out of curiousity I tried testing these out and neither seem to work ?
      use DBI;
use DBD::Oracle;

$dsn = "dbi:Oracle:MYSID";
$dbuser = "myuser/mypass";
my $dbh = DBI->connect($dsn, $dbuser, '', { AutoCommit => 1, PrintErro
+r => 0 });

unless($dbh) {
   die "Unable to connect ($DBI::errstr)\n";
   exit 1;
}

@procs{ @{ $dbh->selectall_arrayref( "select spid from v\$process" ) }
+ } = ();

my $xpid = 16405;
if ( exists $procs{ $xpid } ) {
      print "Pid in use : $xpid\n";
}

      [download]
      The $xpid definitely exists in the v$process view. Is there something missing from this ?
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