Mastering Rust - Second Edition

Iterators

An iterator is a construct that provides an efficient way to act on elements of collection types. They are not a new concept, though. In many imperative languages, they are implemented as objects that are constructed from collection types such as lists or maps. For instance, Python's iter(some_list) or C++'s vector.begin() are ways to construct iterators from an existing collection. The main motivation for iterators to exist in the first place is that they provide a higher level abstraction of walking through items of a collection instead of using manual for loops, which are very much prone to off by one errors. Another advantage is that iterators do not read the whole collection in memory and are lazy. By lazy, we mean that the ...