1. Yes, by several means.

use Storable;
store (\@array, "/path/to/array.dat");
my @newarray = @{retrieve("/path/to/array.dat")};
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2. and 3.

while(<>) {
  /^(.+)\: (.+)$/;
  my $key = $1
  my @values = split(", ", $2);
  $hash{$key} = \@values;
}

foreach my $key (sort keys %hash) {
  print "$key:  ", join(", ", @{$hash{$key}}), "\n";
}
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I hope that I understood what you were asking. -xtype