Perl is pretty nice about default values:
: jmglov@laurana; perl -e \'@foo; printf \"%d\\n\", $foo[123]\' 0 : jmglov@laurana; perl -e \'%foo; printf \"%d\\n\
The easiest way would be:
new_array = Array.new(size, default_value)
For example:
new_array = Array.new(5,"foo")