Clojure Programming/Examples/API Examples/Data Structures
Numbers
[edit | edit source]Computation
[edit | edit source]+
[edit | edit source]Returns the sum of nums. (+) returns 0.
(+ [] [x] [x y] [x y & more])
user=> (+ 1 2 3)
6
user=> (map + [1 2 3] [1 1 2])
(2 3 5)
-
[edit | edit source]If no ys are supplied, returns the negation of x, else subtracts the ys from x and returns the result.
(- [x] [x y] [x y & more])
user=> (- 1 2 3)
-4
user=> (- -1)
1
*
[edit | edit source]Returns the product of nums. (*) returns 1.
(* [] [x] [x y] [x y & more])
user=> (* 1 2 3 4)
24
/
[edit | edit source]If no denominators are supplied, returns 1/numerator, else returns numerator divided by all of the denominators.
(/ [x] [x y] [x y & more])
user=> (/ 1 4)
1/4
inc
[edit | edit source]Returns a number one greater than num.
(inc [x])
user=> (inc 41)
42
user=> (inc 1/4)
5/4
dec
[edit | edit source]Returns a number one less than num.
(dec [x])
user=> (dec 99)
98
user=> (map dec [2 3 4])
(1 2 3)
min
[edit | edit source]Returns the least of the nums.
(min [x] [x y] [x y & more])
user=> (min 2 -1 3)
-1
max
[edit | edit source]Returns the greatest of the nums.
(max [x] [x y] [x y & more])
user=> (max 2 -1 3)
3
quot
[edit | edit source]Quotient of dividing numerator by denominator.
(quot [num div])
user=> (quot 4 2)
2
user=> (quot 5 2)
2
user=> (quot 6 2)
3
rem
[edit | edit source]Remainder of dividing numerator by denominator.
(rem [num div])
user=> (rem 5 2)
1
user=> (rem 4 2)
0
rationalize
[edit | edit source]Returns the rational value of num.
(rationalize [num])
user=> (rationalize 1.33)
133/100
user=> (rationalize 3.14159265)
62831853/20000000
user=> (rationalize (Math/sqrt 2))
14142135623730951/10000000000000000
Comparison
[edit | edit source]==
[edit | edit source]Returns non-nil if nums all have the same value, otherwise false.
(== [x] [x y] [x y & more])
user=> (== (+ 1 2) 3)
true
user=> (== (+ 1 2) 3 2.999)
false
user=> (if (== 2 (+ 1 1)) (println "So easy!"))
So easy!
user=> (== true true) ;Be careful! Works only for nums.
false
user=> (= true true) ;= works like Java x.equals(y)
true
<
[edit | edit source]Returns non-nil if nums are in monotonically increasing order, otherwise false.
(< [x] [x y] [x y & more])
user=> (< 1 (Math/sqrt 2) (+ 1 1))
true
user=> (< 5 5)
false
user=> (< 5)
true
>
[edit | edit source]Returns non-nil if nums are in monotonically decreasing order, otherwise false.
(> [x] [x y] [x y & more])
user=> (> 7 6 4 2)
true
user=> (> 2 4)
false
<=
[edit | edit source]Returns non-nil if nums are in monotonically non-decreasing order, otherwise false.
(<= [x] [x y] [x y & more])
user=> (<= 0 1 1)
true
>=
[edit | edit source]Returns non-nil if nums are in monotonically non-increasing order, otherwise false.
(>= [x] [x y] [x y & more])
user=> (>= 3 2 1)
true
Predicates
[edit | edit source]zero?
[edit | edit source]Returns true if num is zero, else false.
(zero? [x])
user=> (zero? 0.01)
false
user=> (zero? 0)
true
pos?
[edit | edit source]Returns true if num is greater than zero, else false.
(pos? [x])
user=> (pos? 0)
false
user=> (pos? (Math/PI))
true
user=> (filter pos? [-1 1 0 -1 5 2])
(1 5 2)
neg?
[edit | edit source]Returns true if num is less than zero, else false.
(neg? [x])
user=> (neg? -1)
true
user=> (neg? 0)
false
Strings
[edit | edit source]str
[edit | edit source]user=> (str "a" :b \c 3 4.5 6/7)
"a:bc34.56/7"
user=> (str [1 2])
"[1 2]"
user=> (str 1 2)
"12"
user=> (str #(1))
"user$eval__1289$fn__1291@4f53dd"
Characters
[edit | edit source]user=> \a
\a
user=> (seq "a")
\a
user=> (seq " ")
(\space)
user=> (char 13)
\return
user=> (str \a \b \c)
"abc"
user=> (char? \z)
true