获取随机字符串(Clojure)

处女贴，不知道写什么，把今天在群里讨论的贴上来好了。

 (defn ^String rand-str [N] 
  (loop [sb (StringBuilder. "") 
         x N  
         s (get "0123456789" (rand-int 10))]
     (if (> x 0) 
         (recur (-> sb (.append s)) (- x 1) 
                 (get "0123456789" (rand-int 10)))  
          (str sb)))
  )

 (rand-str 15)

这个是我写的，不喜欢(get "0123456789" (rand-int 10)) 两次，又改：

  (defn ^String rand-str [N] 
  (loop [sb (StringBuilder. "") 
         x ( + 1 N)  
         s \ ]
     (if (> x 0) 
         (recur (-> sb (.append s)) (- x 1) 
                 (get "abcdefghijklmnopqrstuvwxyz0123456789" (rand-int 37)))  
          (clojure.string/trim sb)))
   )

(rand-str 10)

不过我觉得群友的更简洁一些：

  (defn rand-str [n] 
   (clojure.string/join (repeatedly n 
           #(rand-nth "abcdefghijklmnopqrstuvwxyz0123456789"))))
   (rand-str 10)

还有人这样写：

(subs (str (Object.)) 17)