Suppose I want to apply the parameter p1 and p2 to a list of function calls:
(defn some-func [] (let [p1 a p2 b] (f1 p1 p2) (f2 p1 p2) (f3 p1 p2) ... )) What's a good and concise way of doing this?
- 3It would be great if you accepted some of the answers to your questions.akond– akond2020-02-10 04:48:30 +00:00Commented Feb 10, 2020 at 4:48
- 4Do you want to apply those functions just for "side effects" or you want to use their return values?Juraj Martinka– Juraj Martinka2020-02-10 05:11:17 +00:00Commented Feb 10, 2020 at 5:11
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3 Answers
Assuming you want just side-effects, I'd use doseq to force the calls; iterate the functions you want to call. e.g.
user=> (doseq [f [println println println]] (f 1)) 1 1 1 nil 
Comments
You may want to review the Clojure CheatSheet. The function juxt can do what you want.
Beware, though, juxt is somewhat obscure and can make it hard to read your code.
3 Comments
zengod
juxt returns a vector. What I really want is these function calls in a sequence. I tried (lazy-seq (juxt...)), but it says "Can't convert lazyseq to IFn".
zengod
i.e., how do I convert the vec to IFn?
Alan Thompson
Read the docs on the 2 links above, esp the 2nd one to clojuredocs.org
You can use for or map, both of which return a clojure.lang.LazySeq. Small working example:
(defn f1 [x y] (+ x y)) (defn f2 [x y] (- x y)) (defn f3 [x y] (* x 1)) ;; Method 1 - for (for [f [f1 f2 f3]] (f 10 5)) ;; => (15 5 50) ;; Method 2 - map (map #(% 10 5) [f1 f2 f3]) ;; => (15 5 50) 