use Data::Dumper;
use strict;
use warnings;
my $hoa = {a => [1,2],  'b'=>[1,3], c=> [2,0]};
my $s = Dumper $hoa;
$s =~ s/^\s+//mg;
$s =~ s/(?<!(\],| {))[\r\n]//sg;
print $s; print "\n";