How about:

my (@h,@c);
push @h, $_->{hour} foreach(@{$data});   # no so great
push @c, $_->{count} foreach(@{$data});  # see extremely's comment 
my $new = [ \@h, \@c ];

$gd = $graph->plot($new);                # wrong - see orbital's comme
+nt
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BEFORE:                          AFTER:
$VAR1 = [                        $VAR1 = [
          {                                [  
            'count' => 5,                     1,
            'hour' => 1                       5,
          },                                  2
          {                                ],
            'count' => 2,                  [
            'hour' => 5                       5,
          },                                  2,
          {                                   8
            'count' => 8,                  ]  
            'hour' => 2                  ];
          }
        ];
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Jeff

R-R-R--R-R-R--R-R-R--R-R-R--R-R-R--
L-L--L-L--L-L--L-L--L-L--L-L--L-L--

merlyn showed ya map but honestly you shouldn't get into the habit of traipsing through a data set multiple times. When ever you see two lines that both end "foreach (@array)" you should be doing:

foreach (@data) {
push @h, $_->{'hour'};
push @c, $_->{'count');
}
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You get in a hurry and do it wrong then wind up going through the same data like 7 or 8 times when there are 100,000 items in the list and you are going start wondering where your afternoon of surfing PM went. =P

--
$you = new YOU;
honk() if $you->love(perl)

This is perfect except that I had to cange the foreach lines to look like follows.

my (@h,@c);
push @h, $_->{'hour'} foreach(@data);
push @c, $_->{'count'} foreach(@data);
my $new = [ \@h, \@c];
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Now it is graphing correctly

Any kind of push @x, .... for @y should immediately invoke that magic three-letter word, "m a p".

my $new = [ [map $_->{hour}, @data], [map $_->{count}, @data] ];
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-- Randal L. Schwartz, Perl hacker

print IMG $gd->plot(\@data)->png;
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You are correct the error message that I am receiving is

Can't call method "png" on an undefined value at _graph_test.pl line 9
+1, <STDIN> line 1.
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I am still running into trouble with the data. I have changed the code to read like follows

my (@h,@c);
push @h, $_->{'hour'} foreach(@{$data});
push @c, $_->{'count'} foreach(@{$data});
my $new = [ \@h, \@c];
print (\@new);


#@data=(["1st","2nd","3rd"],
#        [9,4,7]);


#  I have a hash table with $data[$index]{'hour'} and $data[$index]{'c
+ount'}
#
$graph= GD::Graph::lines->new(400,300);
$graph->set(
    x_label => 'Hour',
    y_label => 'Transaction Volume',
    title => 'Number of transactions per hour',
    y_max_value => 20,
    y_label_skip => 1,
    y_tick_number => 1);

    #$gd = $graph->plot(\@data);

    open (IMG,'>file.png') or die $!;
    binmode IMG;
    print IMG $graph->plot(\@new)->png;

    close IMG;
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but when I run it I still receive the same error. If I uncomment the @data lines and plot to @data instead of @new it works. Any ideas?

because $new is an array reference, so all you need to do is fill it in as $graph->plot($new)->png;

$new is a already a reference to an array consisting of two arrayrefs. There is no such thing (yet) as @new in the code snippet you've posted. Try it with

print IMG $graph->plot($new)->png;
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(instead of the \@new you have there now) and see what happens.

use strict should have caught this. You *are* using, strict, aren't you?

Philosophy can be made out of anything. Or less -- Jerry A. Fodor