clojure cheat sheet

gistfile1.clj

; this is a comment

; this is a double function
(defn doublen [x] (* x 2))

; basic collections (lists, vectors, maps)
(def a-list '(1 2 3))
(def a-vector [1 2 3])
(def a-map {:key1 val1 :key2 val2})

; other collections
(sorted-map :a 1 :b 2) ; this is a sorted map

; for each type of the collection generic functions
(count coll)     ; counts the elements
(conj coll item) ; add something to the collection
                 ; for maps it joins items of 2 maps (overwrites the old one
                 ;                                    if there is a collision)
(seq coll)       ; sequence

; conj on list - prepends the element to the front
(conj '(1 2 3) 4) ; (4 1 2 3)

; conj on vector - appends to the end
(conj [1 2 3] 4)  ; [1 2 3 4]

; conj on map - joins 2 maps

; other collection functions
(first  '(1 2 3)) ; 1
(second '(1 2 3)) ; 2
(rest   '(1 2 3)) ; (2 3)
(last   '(1 2 3)) ; 3

; peek and pop are like first and rest
; work on lists and vectors differeny

(assoc vector index val) ; associates index with value
(get vector index)       ; gets the element at index
(nth vector index)       ; like get but returns an exeption
(subvec vector start end) ; subvector - start inclusive, end exclusive