use warnings;
[download]

perl -MData::Dumper -we "$array[2,2] = 'foo'; print Dumper \@array"
[download]

Multidimensional syntax $array[2,2] not supported at -e line 1.
Useless use of a constant in void context at -e line 1.
$VAR1 = [
          undef,
          undef,
          'foo'
        ];
[download]

$athlete[$i][$j++] = $bug;
[download]

-enlil

Well, if I change the algorithm to :

  $qry = $DB->Query("SELECT * FROM recipes WHERE type = '$type' ORDER 
+BY rand()
limit $quantity") || die "Got error on select: $Mysql::db_errstr\n";
                                                                      
+          
  for ($i=0; $i<$qry->numrows; $i++) {
    @row = $qry->fetchrow or warn "recipes didn't find a matching row"
+;
    print "\@row is assigned @row\n";
    $j = 0;
    foreach my $bug (@row) {
      $athlete[$i][$j++] = $bug ;
      print "\$i\$j is assigned $i:$j\n";
      print "\$athlete[\$i,\$j] is assigned the value $athlete[$i][$j]
+\n";
      print "\$bug is assigned the value $bug\n";
    }
  }
}
[download]

then it yields:

@row is assigned 33 Small Bunch Grapes carb 15 0.4 0.1
$i$j is assigned 4:1
Use of uninitialized value in concatenation (.) or string at ./getCurr
+entNeeds.pl line 74.
$athlete[$i,$j] is assigned the value
$bug is assigned the value 33
$i$j is assigned 4:2
Use of uninitialized value in concatenation (.) or string at ./getCurr
+entNeeds.pl line 74.
$athlete[$i,$j] is assigned the value
$bug is assigned the value Small Bunch Grapes
$i$j is assigned 4:3
Use of uninitialized value in concatenation (.) or string at ./getCurr
+entNeeds.pl line 74.
$athlete[$i,$j] is assigned the value
$bug is assigned the value carb
$i$j is assigned 4:4
Use of uninitialized value in concatenation (.) or string at ./getCurr
+entNeeds.pl line 74.
$athlete[$i,$j] is assigned the value
$bug is assigned the value 15
$i$j is assigned 4:5
Use of uninitialized value in concatenation (.) or string at ./getCurr
+entNeeds.pl line 74.
$athlete[$i,$j] is assigned the value
$bug is assigned the value 0.4
$i$j is assigned 4:6
Use of uninitialized value in concatenation (.) or string at ./getCurr
+entNeeds.pl line 74.
$athlete[$i,$j] is assigned the value
$bug is assigned the value 0.1
[download]

The error lies in the fact that you are incrementing $j here:

$athlete[$i][$j++] = $bug;
[download]

The problem is that since $j is one larger than before, and thus you are not printing out the same thing (2 lines later) as what you just set. (ie $athlete[0][0] != $athlete[0][1]) so you get the warning.

you might want to increment the $j by one at the end of the loop.

update: I am afraid, I might have confused you so here goes. Let's pretend we are going through the inner loop on the first pass:

$j = 0;
foreach my $bug (@row) {
  #here $j == 0; so the following line would be
  #$athlete[$i][0] = $bug;

  $athlete[$i][$j++] = $bug 

  #at this poing the $j == 1 because of the $j++
  #on the previous line.
  print "\$i\$j is assignt $i:$j\n";
  print "\@athlete[\$i,\$j] is assigned the value $athlete[$i][$j]\n";

  #on the previous line you $j == 1 so you are refering to
  #$athlete[$i][1] which is not the same as what you set
  #but rather the value you will set the next time through.
  . . .
[download]

if you change the print line to:

print "\@athlete[\$i,\$j] is assigned the value $athlete[$i][$j-1]\n";
[download]

you would print the value you just set, which is what I think you are trying to do.

-enlil

Try this instead...


$i = 0;
while (@row = $qry->fetchrow)
{
    print "\@row is assigned @row\n";
    $j = 0;
    foreach my $bug (@row)
    {
      $athlete[$i][$j] = $bug ;
      print "\$i\$j is assigned $i:$j\n";
      print "\$athlete[\$i,\$j] is assigned the value $athlete[$i][$j]
+\n";
      print "\$bug is assigned the value $bug\n";
      $j++;
    }
    $i++;
}
[download]

@athlete[$i,$j++] = $bug ;
[download]

$athlete[$i,$j++] = $bug;
[download]

Did you try running

    $athlete[$i,$j++] = $bug;
[download]

with warnings on? It doesn't mean at all what you thing it means.

    $ perl -wcle '$i = $j = 0; $athlete [$i, $j ++] = 1'
    Multidimensional syntax $athlete [$i, $j ++] not supported at -e l
+ine 1.
    Useless use of a variable in void context at -e line 1.
    Name "main::athlete" used only once: possible typo at -e line 1.
    -e syntax OK
[download]

If you want to use multi-dimensional arrays, you have to use the correct syntax:

    $athlete [$i] [$j ++] = $bug;
[download]

Abigail

Your change yielded these results:

@athlete[$i,$j] is assigned the value 0.4 Small Bunch Grapes
$bug is assigned the value 32
$i$j is assigned 4:2
@athlete[$i,$j] is assigned the value 0.4 carb
$bug is assigned the value Medium Pear
$i$j is assigned 4:3
@athlete[$i,$j] is assigned the value 0.4 15
$bug is assigned the value carb
$i$j is assigned 4:4
@athlete[$i,$j] is assigned the value 0.4 0.4
$bug is assigned the value 16
$i$j is assigned 4:5
@athlete[$i,$j] is assigned the value 0.5 0.1
$bug is assigned the value 0.5
$i$j is assigned 4:6
@athlete[$i,$j] is assigned the value 0.5
$bug is assigned the value 0.2
[download]

To be honest, I'm more confused now than I was when I first made this post.

You need to replace all @athlete[$i,$j] with $athlete[$i,$j], even with your print statement. Because the syntax @athelete[$i,$j] is wrong. ;-)

To understand why, you need to understand what is an array slice ...

@row is assigned 31 Medium Orange carb 14 2 0.2
@athlete[$i,$j] is assigned the value
@athlete[$i,$j] is assigned the value Medium Orange
@athlete[$i,$j] is assigned the value carb
@athlete[$i,$j] is assigned the value 14
@athlete[$i,$j] is assigned the value 2
@athlete[$i,$j] is assigned the value 0.2
@row is assigned 42 1/2 c. (cooked) past carb 19.5 3.2 0.4
@athlete[$i,$j] is assigned the value 42 42
@athlete[$i,$j] is assigned the value
@athlete[$i,$j] is assigned the value carb
@athlete[$i,$j] is assigned the value 19.5
@athlete[$i,$j] is assigned the value 3.2
@athlete[$i,$j] is assigned the value 0.4
@row is assigned 26 1/2 c. canned peache carb 14 1 0
@athlete[$i,$j] is assigned the value 26 0.4
@athlete[$i,$j] is assigned the value 1/2 c. canned peache 1/2 c. cann
+ed peache
@athlete[$i,$j] is assigned the value
@athlete[$i,$j] is assigned the value 14
@athlete[$i,$j] is assigned the value 1
@athlete[$i,$j] is assigned the value 0
@row is assigned 6 White Bread III carb 24.5 4.1 2.3
@athlete[$i,$j] is assigned the value 6
@athlete[$i,$j] is assigned the value White Bread III 0
@athlete[$i,$j] is assigned the value carb carb
@athlete[$i,$j] is assigned the value
@athlete[$i,$j] is assigned the value 4.1
@athlete[$i,$j] is assigned the value 2.3
@row is assigned 20 Marias Spanish Rice carb 42.4 4.3 5
@athlete[$i,$j] is assigned the value 20
@athlete[$i,$j] is assigned the value Marias Spanish Rice
@athlete[$i,$j] is assigned the value carb 2.3
@athlete[$i,$j] is assigned the value 42.4 42.4
@athlete[$i,$j] is assigned the value
@athlete[$i,$j] is assigned the value 5
[download]

It has everything to do with data types! @athelete[$i,$j], $athelete[$i, $j] and $athelete[$i][$j] are completely different. Try to use the Data::Dumper to investigate why:

use strict;
use Data::Dumper;

my @array;

for (my $i=0;$i<2;$i++)
{
  for (my $j=0;$j<2;$j++)
  {
     @array[$i, $j] = "$i.$j";
  }
}
print "Case 1...\n";
print Dumper(@array);

for (my $i=0;$i<2;$i++)
{
  for (my $j=0;$j<2;$j++)
  {
     $array[$i][$j] = "$i . $j";
  }
}
print "Case 2...\n";
print Dumper(@array);

for (my $i=0;$i<2;$i++)
{
  for (my $j=0;$j<2;$j++)
  {
     $array[$i, $j] = "$i . $j";
  }
}
print "Case 3...\n";
print Dumper(@array);
[download]

You will get -

Case 1...
$VAR1 = undef;
$VAR2 = undef;
Case 2...
$VAR1 = [
          '0 . 0',
          '0 . 1'
        ];
$VAR2 = [
          '1 . 0',
          '1 . 1'
        ];
Case 3...
$VAR1 = '1 . 0';
$VAR2 = '1 . 1';
[download]

As you can see, only case 2 gives you what you want, a two dimensional array.

Just one point , when using Data::Dumper::Dumper() to dump an array or a hash, it is often better to pass a reference to the hash/array, as the output looks more like the original data structure - and you avoid the copying overhead of call-by-value vs call-by-refernce

use Data::Dumper;
my @array = (1,2,3,4,5,6,7);
print Dumper(\@array);
my %hash;
# below is a hash slice - you should learn about these
@hash{@array} = @array;# a hash whose keys == its values
print Dumper(\%hash);
[download]

results in the output

$VAR1 = [
          1,
          2,
          3,
          4,
          5,
          6,
          7
        ];
$VAR1 = {
          '7' => 7,
          '1' => 1,
          '2' => 2,
          '3' => 3,
          '4' => 4,
          '5' => 5,
          '6' => 6
        };
[download]

which to my eyes seems nicer

  for ($i=0; $i<$qry->numrows; $i++) {
    @row = $qry->fetchrow or warn '...';
    print "\@row is assigned @row\n";
    $athlete[$i] = [ @row ];
  }
[download]

  for my $i (0 .. $qry->numrows - 1) {
    @row = $qry->fetchrow() or warn '...';
    $athlete[$i] = [ @row ];
  }
[download]

  for (1 .. $qry->numrows) {
    @row = $qry->fetchrow() or warn '...';
    push @$athlete, [ @row ];
  }
[download]

Update: Oops, and again i coded rusbish. Fixed code no3, now it no longer looks bad ;)