partial

(partial f arg1)

(partial f arg1 arg2)

(partial f arg1 arg2 arg3)

(partial f arg1 arg2 arg3 & more)

partial 接受一个函数 f ， 以及少于正常 f 所接受参数数量的参数， 并返回一个匿名函数。

当这个匿名函数被调用时， 传给它的附加参数（additional args）会和之前给定的参数一起， 传给函数 f 。

user=> (def three-times (partial * 3))
#'user/three-times

user=> (three-times 10)                     ; (* 3 10)
30

user=> (three-times 20)                     ; (* 3 20)
60

user=> (defn add-x-y-z [x y z]
           (+ x y z))
#'user/add-x-y-z

user=> (def add-y-z (partial add-x-y-z 0))  ; x = 0
#'user/add-y-z

user=> (def add-z (partial add-y-z 1))      ; y = 1
#'user/add-z

user=> (add-z 2)                            ; z = 2
3                                           ; (+ 0 1 2)

讨论

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