Question

可能重复：
Mapping over sequence with a constant

我正在尝试执行以下操作（仅作为示例）：

(defn f [x param] ( 
  ; do something with "x" AND with "param"
  ))
(defn filtered-list [param] (map f ["a" "b" "c"]))
; called later as
(filtered-list 123)
; expected calls are: (f "a" 123), (f "b" 123) and (f "c" 123)

因此，我需要找到一种方法将param传递给f，由map使用。 Clojure有可能吗？此功能也可称为"functional closure"。

Answer 1

使用partial从f创建一个curried函数，传递param

(defn f [param x] ( 
  ; do something with "x" AND with "param"
  ))

(defn filtered-list [param] (map (partial f param) ["a" "b" "c"]))

Answer 2

如何使用partial？

(defn f [param x]  
    (str param \- x) ;; do something
)

(defn filtered-list 
    [param] 
    (map (partial f param) ["a" "b" "c"]))

但是，您必须更改f的参数顺序。

使用常量参数将函数应用于集合的元素

2 个答案: