You do not have 2 array parameters, you have 2 lists. And the answer is: because Perl is designed to flatten lists - and arrays in list contexts are lists with the array elements. The answer to the second question is: you cannot. You can, however, pass two references to arrays to a sub: 
mysub([1..5],[6..9]);
sub mysub {
    my @array1 = @{$_[0]};
    my @array2 = @{$_[1]};
}

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In reply to Re: why perl joins multy list parameters to one list by JavaFan
in thread why perl joins multy list parameters to one list by Achilles_Sea

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