in reply to better way to convert a string into an array and an hash

Looks good to me. I'd write it like this: 
my $string = " ... ";
my (@array_2, %hash_1);
foreach ( split ',' => $string ) {
    my ($left, $right) = split ':';

    push @array_2, $left;
    $hash_1{$left} = $right;
}

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You don't need @array_1 at all. You should scope @array_temp more tightly. And, in fact, I would label the actual items of @array_temp. Otherwise, it looked fine.

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