Loading specific columns into arrays

sidsinha has asked for the wisdom of the Perl Monks concerning the following question:

Hello Monks!!! Good Day...

I am trying a simple graph/chart plot but I have a string which contains data that can be split with "/\s+/" however, the data with which I want to plot the graph lies in column 3 and column 4.

I tried to load the contents of $tb2 into an array @plot_data and loop through the array but I do not get what I expect. Could you please correct me from what I have done. I know its fairly simple but my bad


#!/usr/bin/env perl -l

use strict;
use warnings;
use GD::Graph::bars; 

#in my code, the value of $tb2 below is returned by another function, 
+below is for simplicity, but this is how my string looks like.

my $tb2="Date       Start Time End Time  Egress     Sent 
         08-15-2013 00:22:22   00:22:29   16.53     3.85 
         08-15-2013 01:22:22   01:22:28   17.05     3.6  
         08-15-2013 02:22:23   02:22:28   16.79     3.61 
         08-15-2013 03:22:24   03:23:27  103.89    37.29 
             08-15-2013 04:22:24   04:22:26    2.1      0.18 
             08-15-2013 11:22:25   11:25:11   73.72    60.98 
             08-15-2013 12:22:25   12:27:55  146.65   133.68"

####What I tried:

my @plot_data=(split '/\s+/',$tb2);
for (@plot_data){
 print $plot_data[1];
 
 my @graph = (
 ["$plot_data[1]"],
 ["$plot_data[4]"],
 ["$plot_data[5]"],
 );
}         

####What I am trying to do:         
#    my @graph = (
#    [#all columns in "Egress" from $tb2, seperated by comma],
#    [#all columns in "Sent" from $tb2, seperated by comma],
#    );

        for my $my_graph (GD::Graph::bars->new)
        {
        print STDERR "Processing Graph\n"; 
        $my_graph->set( 
        x_label => 'Timestamp', 
        y_label => 'Data Conveyed/Sent', 
        title => 'Conveyed Vs. Sent', 
        long_ticks => 1, 
        y_max_value => 200, 
        y_tick_number => 8, 
        y_label_skip => 2, 
        bar_spacing => 3, 
        shadow_depth => 4, 
accent_treshold => 200, 
transparent => 0, 
); 
print @graph;
open(IMG, '>file.gif') or die $!;
  binmode IMG;
$my_graph->set_legend('Conveyed', 'Sent'); 
my $gd = $my_graph->plot(\@graph); 
#save_chart($my_graph, "Graph"); 
 print IMG $gd->gif;
   close IMG;

}
[download]

Comment on Loading specific columns into arrays Download Code

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Re: Loading specific columns into arrays by kcott (Archbishop) on Aug 16, 2013 at 09:45 UTC
G'day sidsinha, "I have a string which contains data that can be split with "/\s+/" however, the data with which I want to plot the graph lies in column 3 and column 4." Just ignore the values you don't want by assigning them to `undef`. Here's the technique (I'm assuming there's no Column 0): `$ perl -Mstrict -Mwarnings -le ' my $x = "a b c d"; my (undef, undef, $c, $d) = split /\s+/ => $x; print "$c $d"; ' c d` [download] Update: That looks a tad clunky. Instead, you can take a slice of the `split` results: this might be better if you have more than four columns. `$ perl -Mstrict -Mwarnings -le ' my $x = "a b c d"; my ($c, $d) = (split /\s+/ => $x)[2,3]; print "$c $d"; ' c d` [download] -- Ken	[reply] [d/l] [select]
Re: Loading specific columns into arrays by poj (Abbot) on Aug 16, 2013 at 13:08 UTC
I'm guessing this is what you want, a 2 bar graph #!perl use strict; use warnings; use GD::Graph::bars; my $tb2 = "Date Start Time End Time Egress Sent 08-15-2013 00:22:22 00:22:29 16.53 3.85 08-15-2013 01:22:22 01:22:28 17.05 3.6 08-15-2013 02:22:23 02:22:28 16.79 3.61 08-15-2013 03:22:24 03:23:27 103.89 37.29 08-15-2013 04:22:24 04:22:26 2.1 0.18 08-15-2013 11:22:25 11:25:11 73.72 60.98 08-15-2013 12:22:25 12:27:55 146.65 133.68"; my @records = split /\n/,$tb2; my $header = shift @records; my @graph=([],[],[]); for my $line (@records){ my @f = split /\s+/,$line; print join '\|',@f,"\n"; push $graph[0],"$f[0] $f[1]"; push $graph[1],$f[3]; push $graph[2],$f[4]; } my $my_graph = GD::Graph::bars->new(600,450); print STDERR "Processing Graph\n"; $my_graph->set( x_label => 'Timestamp', x_labels_vertical => 1, y_label => 'Data Conveyed/Sent', title => 'Conveyed Vs. Sent', long_ticks => 1, y_max_value => 200, y_tick_number => 8, y_label_skip => 2, bar_spacing => 3, bargroup_spacing => 10, shadow_depth => 4, accent_treshold => 200, transparent => 0, ); $my_graph->set_legend('Conveyed', 'Sent'); my $gd = $my_graph->plot(\@graph); # save graph my $gif = 'file.gif'; open(IMG, '>',$gif) or die "Could not open $gif $!"; binmode IMG; print IMG $gd->gif; close IMG; print "$gif created\n"; [download] poj	[reply] [d/l]
Re: Loading specific columns into arrays by Anonymous Monk on Aug 16, 2013 at 09:44 UTC
what I tried: which obviously did not yield my results. Where did you add that, and what did you hope it would do? What happened instead?	[reply]
Re^2: Loading specific columns into arrays by sidsinha (Acolyte) on Aug 16, 2013 at 09:47 UTC
Update: Updated section "what I tried" and "what I am trying to do"	[reply]
Re^3: Loading specific columns into arrays by Anonymous Monk on Aug 16, 2013 at 10:15 UTC
Can you tell me what my does? Can you tell me the lifespan of @graph? Taking some advice from Basic debugging checklist lets see what you have so far Read more... (480 Bytes) So there is 1)problem with your split invocation If you copy/paste from split documentation or your previous post Regex for non-patterned input a corrected split invocation, you have Read more... (572 Bytes) Do you see any issues with this? Do you see what your next step should be?	[reply] [d/l] [select]
Re: Loading specific columns into arrays by ww (Archbishop) on Aug 16, 2013 at 11:26 UTC
"034: # [#all columns in "Egress" from $tb2, seperated by comma]," Nope, "Egress" is the heading of a column; perhaps you mean "all rows in...."	[reply]