I know this is just an example, but strict and warnings can help nonetheless. In this case you define @arrray and loop over @array. OK, that's out of my system. :-)

A dispatch table might help, especially if you've got a lot of special cases. For example:

my %dispatch =
    (
        '#' => \&sub1,
        1 => \&sub2,
    );

my @array = (1, 2, 3, '#', 6, 7, '#', 9, 10); # corrected typo!
foreach (@array) {

    if( exists $dispatch{$_} )
    {
        $dispatch{$_}->();
    }
    else
    {
        sub3();
    }
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