Iterators

• enable lazy evalutation - delay evaluation of an expression until its value is needed

Iterable

• an object capable of returning its members one at a time

• all sequences - (lists, strings, tuples)

Iterators

• an object that provides sequential access to values one-by-one

• all iterators are iterables, not all iterables are iterators

Metaphor: Iterables are books & Iterators are bookmarks (Possibly several iterators for an iterable).