Convert hash into csv file

First step:

• use strict; says:
  • Bareword "Honda" not allowed while "strict subs" in use at xx.pl line 4.

That is not an approved way of creating the hash. I suggest:

use strict;
use warnings;

my %hash = (
Honda  => { Blue => '10', Red => '10', Yellow => '60' },
Ford   => { Blue => '20', Red => '25', Yellow => '26' },
Toyota => { Blue => '17', Red => '16', Yellow => '18' },
);

Then, you should probably use Text::CSV. However, it is not all that hard to do output with simple manipulation. We can exploit the fact that you've asked for blue, red, yellow which happen to be in alphabetic order:

print "make,blue_volume, red_volume,yellow_volume\n";
foreach my $make (sort keys %hash)
{
    print "$make";
    foreach my $colour (sort keys %{$hash{$make}})
    {
        print ",$hash{$make}{$colour}";
    }
    print "\n";
}

For the sample hash, the output is:

make,blue_volume, red_volume,yellow_volume
Ford,20,25,26
Honda,10,10,60
Toyota,17,16,18

If there was any risk of needing to use quotes or anything else, I'd use Text::CSV.

A solution with List::MoreUtils.

#!/usr/bin/env perl
use warnings;
use 5.012;
use List::MoreUtils qw/first_index/;
use Text::CSV;

my $file_out = 'my_new_file.csv';

my %hash = (
'Honda.Blue' => '10',
'Honda.Red' => '10',
'Honda.Yellow' => '60',
'Ford.Blue' => '20',
'Ford.Red' => '25',
'Ford.Yellow' => '26',
'Toyota.Blue' => '17',
'Toyota.Red' => '16',
'Toyota.Yellow' => '18',
);

my @brands = qw( Honda Ford Toyota );
my @colors = qw( Blue Red Yellow );
my @array;
for my $key ( keys %hash ) {
    my( $brand, $color ) = split /\./, $key, 2;
    my $idx_1 = first_index { $_ eq $brand } @brands;   
    my $idx_2 = first_index { $_ eq $color } @colors;
    $array[$idx_1][0] = $brand;
    $array[$idx_1][$idx_2+1] = $hash{$key};
}

my $csv = Text::CSV->new ( { binary => 1, eol => $/, auto_diag => 2 } ) 
or die Text::CSV->error_diag();
my $col_names = [ qw( Make blue_volume red_volume yellow_volume ) ];
open my $fh, '>:encoding(UTF-8)', $file_out or die $!;
$csv->print ( $fh, $col_names );
$csv->print ( $fh, $_ ) for @array;
close $fh;

If you iterate over the hash and make a line for each key, you will have each make repeated three times; instead, create another hash with all the makes by looping over %hash, extracting the make, and setting $makes{$make} = 1. Then loop over that to produce your lines.

When you extract the make from the %hash key, use /\./ as the split pattern; split always uses a pattern, not a simple string (with one odd exception), and you don't want to split on every character, which is what split '.' would do (thanks, codaddict, for pointing this part out).

'$make.Blue' uses single quotes, so it won't interpolate the variable. Use "$make.Blue" instead.

Move the open and close to before and after the @lines loop, respectively. There's no reason to open the file for each line.

Don't forget a "\n" at the end of each line (unless you are using the -l flag or say instead of print).

Check out Text::CSV::Slurp. It will allow you to turn a hash into CSV and vice versa as well.

For those interested I was able to figure it out, thanks for everyone's help!

my %hash; 
$hash{'aaa.biz'} = 'domainRegistered'; 
$hash{'aaa.com'} = 'domainRegistered'; 
$hash{'aaa.info'} = 'domainRegistered'; 
$hash{'aaa.net'} = 'domainRegistered'; 
$hash{'aaa.org'} = 'domainRegistered'; 

$hash{'bbb.biz'} = 'domainRegistered'; 
$hash{'bbb.com'} = 'domainRegistered'; 
$hash{'bbb.info'} = 'domainRegistered'; 
$hash{'bbb.org'} = 'domainRegistered'; 
$hash{'bbb.us'} = 'domainRegistered'; 

foreach $key (sort keys %hash) 
{   
    @array=split("\\.",$key);
    push (@names, $array[0]); 
}

#Extract unique values and sort
my %seen = ();
my @result = grep { !$seen{$_}++ } @names; 
@names = sort { $a <=> $b } @result;

foreach $element (@names)
{
    foreach $key (sort keys %hash) 
    {   
        @array=split("\\.",$key);
        if (@array [0] eq $element){push (@values, $hash{$key});}
    }
    $values = join(",",@values);
    $line = "$element,$values";
    undef @values;
    push(@lines,$line);
}
print join("\n",@lines);
open (summary, '>>summary.csv');
print summary join("\n",@lines);
close (summary);