For variety, here's a solution that uses a kind of Schwartzian Transform (but grepping instead of sorting).

  my %arr1_as_hash;
  @arr1_as_hash{@arr1} = ();
  my @arr3 =
    map { $_->[1] }
    grep { exists $arr1_as_hash{$_->[0]} }
    map { [ split /,/ ] }
    @arr2;
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jdporter
The 6th Rule of Perl Club is -- There is no Rule #6.