clojure - collections

clojure: about-datatypes.clj

(defn persistent-hash-map [k v]
  "Create PeristentHashMap - performs faster for larger maps" 
  (hash-map k v))
(type (persistent-hash-map :a 1))

(defn persisten-array-map [k v]
  "Create PeristentArrayMap - only suitable for very small maps"
  {k v})
(type (persisten-array-map :a 1))    

; clojure.lang.PeristentHashMap - performs faster for larger maps
(def y {:a 1}) 
(type y)

; clojure.lang.Var
(type (def y {:a 1}))

(def y {:a 1})
; clojure.lang.PeristentHashMap - performs faster for larger maps
(type y)

; clojure.lang.PersistentList
(type '(def y {:a 1}))

; clojure.lang.PeristentArrayMap - only suitable for very small maps
(type {:a 1})

; clojure.lang.PersistentHashSet
(type #{1 2})

{}  ;hash-map
#{} ;hash-set
()  ;list
[]  ;vector