Question

有人可以将此代码转换为clojure吗

BufferedReader br = new BufferedReader(new FileReader(args[0]));

                // Read in first line, if nothing, inputString is null
                String inputString = br.readLine(); // First line is header
                inputString = br.readLine();
    while (inputString != null) {

        rowCount++;
    }

我理解需要使用recur，但是，因为我正在读取文件并且行计数是一个不可变的值，我怎么能增加它以使值在while循环中继续增加。

Answer 1

如果你需要的只是文件中的行数，你可以这样做：

(defn count-lines[file]
  (with-open [r (clojure.java.io/reader file)]
  (count (line-seq r))))

或者，如果你想对每一行做某事（例如，打印它）：

(defn count-lines[file]
   (with-open [r (clojure.java.io/reader file)]
    (loop [i 1
          s (line-seq r)]
          (println (first s))
          (if (seq (rest s))
           (recur (inc i) (rest s)) i))))

Answer 2

(defn read-lines [file]
  (clojure.string/split-lines (slurp file)))

; count the number of lines
(count (read-lines "c:/test.log"))

; returns a list of indexed lines
(map-indexed vector (read-lines "c:/test.log"))
;[[0 "Line 1"]
; [1 "Line 2"]
; [2 "Line 3"]
;  ...]

在clojure中的InputFileStream和while循环

2 个答案: