Note that your sample output is wrong. If going from 4 to 4 changes 0%, than going from 6 to 8 should change 33%, not 133%. Also, you cannot express the change going anywhere from 0.
You might find the following code useful. I have modified some values to show some other interesting results.
#!/usr/bin/perl
use warnings;
use strict;
my %hash = (
file1 => {
foo => 4,
bar => 6,
baz => 4,
quux => 8,
quuux => 6,
quuuux => 0,
},
file2 => {
foo => 4,
bar => 8,
baz => 4,
quux => 8,
quuux => 5,
quuuux => 0,
},
file3 => {
foo => 8,
bar => 0,
baz => 5,
quux => 8,
quuux => 5,
quuuux => 3,
},
);
my %columns = map { $_ => 1 } map keys %{ $hash{$_} }, keys %hash;
my @files = qw/file1 file2 file3/;
for my $column (keys %columns) {
print $column, "\t", $hash{$files[0]}{$column};
for my $i (1 .. $#files) {
my ($this, $previous) = map $hash{ $files[$_] }{$column}, $i,
+$i - 1;
print "\t", $this;
my $change = '-';
if ($previous) {
$change = sprintf "%d%%", 100 * ($this - $previous) / $pre
+vious;
}
print "\t$change";
}
print "\n";
}
Output:
bar 6 8 33% 0 -100%
baz 4 4 0% 5 25%
quuux 6 5 -16% 5 0%
quux 8 8 0% 8 0%
foo 4 4 0% 8 100%
quuuux 0 0 - 3 -