in reply to How best to tell when my hash is "full" (all values defined)?

To answer your question (which is what you asked, not necessarily what you want :) ): use grep. 
my @undefined = grep !defined $stats{$_}, keys %stats;
if(@undefined { 
    local $" = ", ";
    my $undefined = @undefined;
    warn "$undefined values were not defined, for keys (@undefined)\n"
+;
}

[download]

If you just want a simple count, not an elaborate report, you can use the simpler 

my $undefined = grep !defined, values %stats;
warn "$undefined values were not defined\n" if $undefined;

[download]

Replies are listed 'Best First'.
Re^2: How best to tell when my hash is "full" (all values defined)?
by OfficeLinebacker (Chaplain) on Dec 18, 2006 at 15:08 UTC
    bart, thanks for the reply. grep is another one of those functions that I don't know well. Continuing on our theoretical tangent, if you will, could one golf your approach down to 
    grep !defined, values %stats || last;

    [download]

    as a quick and simple escape clause?

    For some reason I like the idea of predeclaring what data I want (by mnemonic), and "filling" an empty data structure, as opposed to creating the key-value pairs on the fly. It's just mental I guess, though I suppose it may increase readability somewhat. Also, is there a memory or performance penalty if you don't predeclare the numer of elements in a hash? Returning the scalar of the hash gives me 4/8 with the predeclared version; I suppose I will try it the other way and report back.

    Thanks again to everyone,
    T.

    I like computer programming because it's like Legos for the mind.
[reply]
[d/l]
      Hi, 
        grep !defined, values %stats || last;
  my $swvn=grep !defined, values %stats;
  print $swvn;
  $swvn || last;

      [download]
      produces 
      3
2
2
0
      so that means it doesn't work. The "fix" is to scalar() what grep() returns: 
        scalar(grep !defined, values %stats) || last;
  my $swvn=grep !defined, values %stats;
  print $swvn;
  $swvn || last;

      [download]
      produces 
      3
2
2
      I'll check the memory consuption thing shortly.
      I like computer programming because it's like Legos for the mind.
[reply]
[d/l]
[select]
      Hi again :) The following code (I plan to implement the piped open shortly, but just used what I have to test the memory usage of the hashes in the two approaches) 
      my @raw=`top -b -n 1`;
my (%stats,%stats2);
my $expected_keys = 5;
@stats{'users','load','tmem','fmem','runproc'} = ();
my $its=0;

foreach my $line (@raw){
  if ($line =~ /up\s.+\s(\d+)\suser.+\s+load\saverage:\s+(\d+\.\d{2}),
+/){
    $stats{users}=$1;
    $stats{load}=$2;
    $stats2{users}=$1;
    $stats2{load}=$2;
  }
  elsif ($line =~ /(?:Tasks|processes):.+\s+(\d+) running/i){
    $stats{runproc}=$1;
    $stats2{runproc}=$1;
  }
  elsif ($line =~ /^Mem:\s+(\d+)k\s+(?:total|av),.+used,\s+(\d+)k\s+fr
+ee/){
    $stats{tmem}=$1;
    $stats{fmem}=$2;
    $stats2{tmem}=$1;
    $stats2{fmem}=$2;
  }
  $its++;
  print scalar(%stats2);
  print scalar(%stats);
  (scalar(keys(%stats2)) == $expected_keys) && last;
} ## end foreach my $line (@raw)

      [download]
      outputs 
      
2/8
4/8
2/8
4/8
2/8
4/8
4/8
4/8
      So the memory usage is no different (correct me if I am wrong--my understanding is that the number we are worried about (if we're worried about memory consumption) is the divisor).

      I'll go ahead and make the call to `top` a piped open and have done with it. Thanks for your help (everyone who posted).

      T.
      I like computer programming because it's like Legos for the mind.
[reply]
[d/l]

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