Clojure分区字符串列表，累加结果

我很抱歉标题不够精确，但这可能说明我缺乏clojure的经验

我正在尝试获取一个大的字符串列表，并将该列表转换为另一个字符串列表，同时进行连接，直到累加器小于某个长度

例如，如果我有

[ "a" "bc" "def" "ghij" ]

我的最大字符串长度是4，我会沿着列表走下去，累加concat，直到累加len>4，然后从头开始累加。我的结果如下：

[ "abc" "def" "ghij" ]

我似乎想不出正确的咒语来划分，这让我有点疯狂。我一直试图使我的累加器成为一个

atom

（但似乎不知道在哪里

重置！

），但除此之外，我不知道在哪里/如何跟踪我累积的字符串

---

提前感谢所有怜悯我的人。

以下是我将如何做到这一点：

(ns tst.demo.core
  (:use demo.core tupelo.core tupelo.test))

(def bound 4)

(defn catter [strings-in]
  (loop [merged-strs    []
         curr-merge     (first strings-in)
         remaining-strs (rest strings-in)]
   ;(newline) (spyx [merged-strs curr-merge remaining-strs])
    (if (empty? remaining-strs)
      (conj merged-strs curr-merge)
      (let          ; try using 'let-spy' instead
        [new-str   (first remaining-strs)
         new-merge (str curr-merge new-str)]
        (if (< (count new-merge) bound)
          (recur merged-strs new-merge (rest remaining-strs))
          (recur (conj merged-strs curr-merge) new-str (rest remaining-strs)))))))

(dotest
  (is=  ["abc" "def" "ghij"]     (catter ["a" "bc" "def" "ghij"]) )
  (is=  ["abc" "def" "ghij"]     (catter ["a" "b" "c" "def" "ghij"]) )
  (is=  ["abc" "def" "ghij"]     (catter ["a" "b" "c" "d" "ef" "ghij"]) )
  (is=  ["abc" "def" "ghij"]     (catter ["a" "bc" "d" "ef" "ghij"]) )
  (is=  ["abc" "def" "ghij"]     (catter ["a" "bc" "d" "e" "f" "ghij"]) )

  (is=  ["abc" "def" "gh" "ij"]  (catter ["abc" "d" "e" "f" "gh" "ij"]) )
  (is=  ["abc" "def" "ghi" "j"]  (catter ["abc" "d" "e" "f" "ghi" "j"]) )

  (is=  ["abcdef" "ghi" "j"]     (catter ["abcdef" "ghi" "j"]) )
  (is=  ["abcdef" "ghi" "j"]     (catter ["abcdef" "g" "h" "i" "j"]) )
)

---

这很接近。我不知道为什么在最后一个字符串的末尾有j

(sequence
 (comp
  (mapcat seq)
  (partition-all 3)
  (map clojure.string/join))
 ["a" "bc" "def" "ghij"]) => ("abc" "def" "ghi" "j")

---

以下是我对此的看法：

（defn折叠[maxlen xs]
（让[concats（take while#）（<（count%）maxlen）（str xs））]
（cons（最后一个concats）（drop（count concats）xs）））
（折叠4[“a”“bc”“def”“ghij]”）
;; => （“abc”“def”“ghij”）

该方法是正确的，但它只在子序列位于输入的开头时起作用。将因以下原因而失败：

（折叠4[“a”“bc”“def”“ghij”“z”“xc”“vbn]）

=>

（“abc”“def”“ghij”“z”“xc”“vbn”）

，或

（折叠4[“asdf”“a”“bc”“def”“ghij]）

（无“asdf”“a”“bc def”“ghij”）

。。感谢所有的回复者——我将把所有的建议作为一种学习经验，并在我理解的时候接受答案。再次感谢！你的确切要求有些不确定。你能看一下我的答案中包含的单元测试，并验证这就是你所寻求的行为吗？谢谢

(sequence
 (comp
  (mapcat seq)
  (partition-all 3)
  (map clojure.string/join))
 ["a" "bc" "def" "ghij"]) => ("abc" "def" "ghi" "j")

(defn catsize [limit strs]
  (reduce (fn [res s]
              (let [base (peek res)]
                (if (> (+ (.length ^String base) (.length ^String s)) limit)
                  (conj res s)
                  (conj (pop res) (str base s)))))
          (if (seq strs) [(first strs)] [])
          (rest strs)))