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#!/usr/bin/perl
#
# Challenge 2: "ASCII bar chart: Write a function that takes a hashref
# where the keys are labels and the values are integer or floating point
# values. Generate a bar graph of the data and display it to stdout.
#
# The input could be something like:
#
# $data = { apple => 3, cherry => 2, banana => 1 };
# generate_bar_graph($data);
#
# And would then generate something like this:
#
# apple | ############
# cherry | ########
# banana | ####
#
# If you fancy then please try this as well: (a) the function could let
# you specify whether the chart should be ordered by (1) the labels, or
# (2) the values.
#
# My notes: easy, especially using a histogram module I wrote recently.
#
use v5.10; # for "say"
use strict;
use warnings;
use Data::Dumper;
use List::Util qw(max);
use Function::Parameters;
#
# my $str = generate_bar_graph( $data, $width, $bylabels );
# Generate a bar graph from the frequency data in $data (a hashref),
# where the maximum frequency occupies $width characters,
# either sorted by labels (if $bylabels is true) or
# by numeric values, returning a printable string form.
#
fun generate_bar_graph( $data, $width, $bylabels )
{
my $maxv = max( values %$data );
my $fieldw = max( map { length($_) } keys %$data );
my $scale = int($width/$maxv);
#die "debug: g_b_g: maxv=$maxv, fieldw=$fieldw, scale=$scale\n";
my @str;
my $fw = $fieldw+2;
my @data = sort {
$bylabels ? $a cmp $b : $data->{$b} <=> $data->{$a}
} keys %$data;
foreach my $k (@data)
{
my $v = $data->{$k};
my $row = sprintf( '%'.$fw.'s | ', $k ). ('#' x ($v*$scale));
push @str, $row;
}
return join("\n", @str );
}
my $data = { apple => 3, cherry => 2, banana => 1 };
my $str = generate_bar_graph( $data, 40, 1 );
say $str;
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