把clojure代码放在一个循环中

Question

(def throws 10) 

(defn r-squared [x y] 
(+ (* (- 0.5 x) (- 0.5 x)) 
    (* (- 0.5 y) (- 0.5 y)))) 

(loop [hits 0] 
    (let [x (rand) 
     y (rand)] 
    ; still inside the let 
    (if (< (r-squared x y) 0.25) ;is it a hit or not? if not, try again 
     (recur (inc hits)) 
     (* 4 (/ hits throws))))) 

我得到了代码工作和运行，直到if条件为真。我该如何重写它，以便将X作为参数并运行X次？

我基本上想打电话给（r-squared 100），并得到多少点击作为返回值。

Answer 1

我认为这是你想要的，如果正确地延伸问题。

(defn test [n] 
    (loop [hits 0 n n] 
    (let [x (rand) 
      y (rand)] 
     (if (< n 0) 
      hits ;// you can put (* 4 (/ hits throws)) here 
      (if (< (r-squared x y) 0.25) 
       (recur (inc hits) (dec n)) 
       (recur hits (dec n))))))) 

Answer 2

没有评估它，所以parn可能会有一点错误。

(def throws 10) 

(defn r-squared [x y] 
(+ (* (- 0.5 x) (- 0.5 x)) 
    (* (- 0.5 y) (- 0.5 y)))) 


(defn test-r-squared [n] 
    (loop [hits (int 0) n (int n)] 
    (let [x (rand) 
     y (rand)] 
    ; still inside the let 
    (if (< n 0) 
     (* 4 (/ hits throws)) 
     (if (< (r-squared x y) 0.25) ;is it a hit or not? if not, try again 
     (recur (inc hits) (dec n)) 
     (recur hits (dec n))))))) 

Answer 3

(defn r-squared [x y] 
(+ (* (- 0.5 x) (- 0.5 x)) 
    (* (- 0.5 y) (- 0.5 y)))) 

(defn hit[] 
    (let [x (rand) y (rand)] 
    (< (r-squared x y) 0.25))) 


(frequencies (for [i (range 1000)] (hit))) ; {true 787, false 213}