(number? x)
Returns true if x is a Number
user=> (number? 1)
true
user=> (number? 1.0)
true
user=> (number? :a)
false
user=> (number? nil)
false
user=> (number? "23")
false
;; map number? over the vector
(map number? [1 0.44 3e6 0xFF])
;;=> (true true true true)
;; map number? over the vector created by converting a list into a vector
;; with the function "into"
(map number? (into [] '(1 0.44 3e6 0xFF)))
;;=> (true true true true)