Re: declaring arrays dynamically

Other replies are right on the nose, you probably want an array of arrays. However, if there is some reason you can't do that (though I can't imagine why not):

while (@data = $sth1->fetchrow_array()) {
    for (my $field = 0; $field <= $#data ; $field++) {
        my $var_cnt = $field+1; #needed for cat in next line to work
        eval('push @field'.$var_cnt.', $data['.$field.'];');
    }
}
[download]

That would generate @field1, @field2,... @fieldn for the width of your row. Using an array of arrays or even a hash would work better. A hash method:

my %results;
while ($data = $sth1->fetchrow_hashref) {
    foreach (keys %$data) {
        push $reults{$_}, $$data{$_};
    }
}
[download]

%results is now a hash of arrays. $results{degree} contains an array of all values for the field "degree" in your table. These can be extracted by:

foreach (keys %results) {
   print "Results for column $_:\n";
   foreach (@{$results{$_}}) {
     print " $_\n";
   }
}
[download]

Or something like it.

^{--

$me = rand($hacker{perl});}

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Re^2: declaring arrays dynamically by ikegami (Patriarch) on Sep 14, 2004 at 18:58 UTC
For fun, `while (@data = $sth1->fetchrow_array()) { for (my $field = 0; $field <= $#data ; $field++) { my $var_cnt = $field+1; #needed for cat in next line to work eval('push @field'.$var_cnt.', $data['.$field.'];'); } }` [download] can be rewritten as `{ no strict 'refs'; while (@data = $sth1->fetchrow_array()) { for (my $field = 0; $field <= $#data ; $field++) { my $var_name = 'field' . ($field+1); push(@$var_name, $data[$field]); } } }` [download] to eliminate the costly eval. You lose the ability to write to lexicals (`my` vars), although using those is just asking for trouble in this scenario. A here's version (with the same caveat as the previous one) that works without (even partially) turning off strict: `my $pkg = \%::; $pkg = $pkg->{$_.'::'} foreach (split(/::/, __PACKAGE__)); while (@data = $sth1->fetchrow_array()) { for (my $field = 0; $field <= $#data ; $field++) { push(@{$pkg->{'field' . ($field+1)}}, $data[$field]); } }` [download] Symtab manipulation is so much fun!	[reply] [d/l] [select]

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Re^2: declaring arrays dynamically
by ikegami (Patriarch) on Sep 14, 2004 at 18:58 UTC

For fun,

while (@data = $sth1->fetchrow_array()) {
    for (my $field = 0; $field <= $#data ; $field++) {
        my $var_cnt = $field+1; #needed for cat in next line to work
        eval('push @field'.$var_cnt.', $data['.$field.'];');
    }
}
[download]

can be rewritten as

{
   no strict 'refs';
   while (@data = $sth1->fetchrow_array()) {
      for (my $field = 0; $field <= $#data ; $field++) {
         my $var_name = 'field' . ($field+1);
         push(@$var_name, $data[$field]);
      }
   }
}
[download]

to eliminate the costly eval. You lose the ability to write to lexicals (my vars), although using those is just asking for trouble in this scenario.

A here's version (with the same caveat as the previous one) that works without (even partially) turning off strict:

my $pkg = \%::;
$pkg = $pkg->{$_.'::'} foreach (split(/::/, __PACKAGE__));

while (@data = $sth1->fetchrow_array()) {
   for (my $field = 0; $field <= $#data ; $field++) {
      push(@{$pkg->{'field' . ($field+1)}}, $data[$field]);
   }
}
[download]

Symtab manipulation is so much fun!

[reply]
[d/l]
[select]