Because slicing takes place on a single array, there isn't a cleaner method than using the map solution you provided, although, you can drop the @ary[0 .. $#ary] for a simple @ary e.g

my @ary = ( [ 1 .. 3 ], [ 4 .. 6 ], [ 7 .. 9 ] );
print map $_->[0], @ary;

__output__

147
[download]

HTH

_________
broquaint