# sequence

## Sequence terms in brief

^  Term  ^  Brief description  ^  Example(s)  ^
| [[Collection]] | A composite data type | [1 2], {:a 1}, #{1 2}, and lists and arrays |
| [[Sequential]] | Ordered series of values | [1 2 3 4], (1 2 3 4) |
| [[Sequence]] | A sequential collection that may or may not exist yet | The result of (map a-fun a-collection) |
| [[Seq]] | Simple API for navigating collections | [[first]], [[rest]], [[nil]], and () |
| [[clojure.core-seq|clojure.core/seq]] | A function that returns an object implementing the seq API | (seq []) ;;=> nil and (seq [1 2]) ;;=> (1 2) |