Clojure循環讀取一個額外的

Question

當長度爲4時，循環執行5次。從流中讀取5個字符。

(loop [i (.read stream) result "" counter length] 
    (let [c (char i)] 
     (println "=>" c) 
     (if (zero? counter) 
     result 
     (recur (.read stream) (str result c) (dec counter))))) 

Answer 1

在做read之前，您應該測試zero?。請注意，即使length == 0開頭，您的版本也會調用read。

(loop [result "" counter length] 
    (if (zero? counter) 
    result 
    (let [c (char (.read stream))] 
     (println "=>" c) 
     (recur (str result c) (dec counter))))) 

避免了另一種方式的明確loop：

(apply str 
     (take length 
      (repeatedly #(let [c (char (.read stream))] 
          (println "=>" c) c))))) 

Answer 2

我不知道Clojure的，但在我看來像你在「結果」的形式再次讀取數據流，在CL這個喜歡最後？