如果矢量大小小于一定量，则conj到clojure矢量

Question

我有三个向量：

final String realPath = ServletContext.getRealPath("/WEB-INF/resources/images/disegno.svg");

final InputStream = new FileInputStream(realPath);

我需要确保向量的大小总是5个元素。我想要一个函数来传递每个将检查大小和结合空字符串作为占位符，当大小小于5时，我得到：

(def v1 ["one" "two" "three"])
(def v2 ["one" "two" "three" "four"])
(def v3 ["one" "two" "three" "four" "five"])

感谢。

Answer 1

你可以使你的vector ++的lazy seq重复空字符串，并从中获取5个元素：

(defn process [items]
  (into [] (take 5 (concat items (repeat "")))))

user> (process ["a" "b"])
["a" "b" "" "" ""]