I have just uploaded a sparse array implementation to CPAN. TipJar::sparse::array::perl::hashbased uses a hash for storage and an array for listing existing keys in order; it provides sparse my @SparseArray; $SparseArray[30123123]="hello"; without requiring using a hundred megabytes of memory. I didn't take a name like "Array::Sparse" because it isn't up to a standard deserving that yet: it is neither in XS nor does it use trees.Thread Next