Iterators: Difference between revisions

Line 138:

Rakus iterators are one direction only (not reversible), and once the iteration has been reified, it is discarded unless explicitly cached. This allows effortless iteration through multi-gigabyte sized data objects and streams without filling up main memory.

The following example iterates though a hash of Positional Iterable objects and demonstrates object slice operations on each; then has a semi contrived example of where directly using iterators may be actually useful in Raku.

The following example iterates though a hash of Positional Iterable objects and demonstrates object slice operations on each; then has a semi contrived example of where directly using iterators may be actually useful in Raku; collating unique ascending values from several infinite sequence generators.

<lang perl6>my %positional-iterable-types =

Line 159:

say "\nWhere iterators really shine; when you are trying to collate the values from several infinite generators.";

my @a = 1, * × 2 … *;

my @i = (1, * × 2 … *).iterator, (1, * × 3 … *).iterator, (1, * × 5 … *).iterator;

my @b = 1, * × 3 … *;

my @c = 1, * × 5 … *;

my @i = [@a.iterator, @b.iterator, @c.iterator];

my @v = @i[0].pull-one, @i[1].pull-one, @i[2].pull-one;