Question

I have an array with a few elements:

MSN = 34.3433423432434%

Chrome = 12.4343434353534%

Gtalk = 32.23233543543532%
…

And I’m passing this array as y-axis labels to use with a module called GD::Graph. The problem I am facing right now, is that the number are so big on the graph that they overlap with the adjacent entry and make it unreadable.

Is there a way where I can round off ALL the elements in an array to just 2 decimal places? And make it xx.xx%?

_{^{Also, anyone familar with using GD::Graph, do you know how can I increase the text-size on the graph? I can increase Title / Legend size fine, but the actual text as in ‘Gtalk’ or ‘32.23233543543532%’ is really small and I’ve tried a lot of the commands from http://search.cpan.org/dist/GDGraph/Graph.pm, but they don’t seem to work for me!}}

Answer 1

#!/usr/bin/perl

use strict; use warnings;
use YAML;

my %x = (
    MSN => '34.3433423432434%',
    Chrome => '12.4343434353534%',
    Gtalk => '32.23233543543532%',
);

for my $x ( values %x ) {
    $x =~ s/^(\d+\.\d+)%\z/ sprintf '%.2f%%', $1/e;
}

print Dump \%x;

Output:

Chrome: 12.43%
Gtalk: 32.23%
MSN: 34.34%

If you want to extract values in a specific order, use a hash slice:

print "@x{ qw( MSN Chrome Gtalk ) }\n";

or, if you just want keys and values to line up in the plot call:

my $gd = $graph->plot([
    [ keys %x ],
    [ @x{ keys %x } ],
]) or die $graph->error;

Note: To increase the text size on a GD::Graph, use a larger font for the element. See Methods for charts with axes.

Using GD::Graph, you really should not have to modify the values yourself. Just provide the string '.2f%%' as the argument to y_number_format.