使用Spectre转换与键匹配的值

Question

I'm sorry if this has been answered elsewhere, but I can't seem to find an example that matches the pattern of what I'm looking for. I also may not yet understand recursive specter paths fully.

If I have the data (explicitly with the nested vector):

{:a "1" :b "2" :c [ {:a "3" :b "4"} {:a "5" :b "6"} ]}

And I'd like to apply the keyword function to all values with the key :a to result in:

{:a :1 :b "2" :c [ {:a :3 :b "4"} {:a :5 :b "6"} ]}

Finally, I'd like it to be recursive to an arbitrary depth, and handle the vector case as well.

I've read https://github.com/nathanmarz/specter/wiki/Using-Specter-Recursively , but I must be missing something critical.

Thanks to anyone pointing me in the right direction!

Answer 1

(use '[com.rpl.specter])
(let [input          {:a "1" :b "2" :c [{:a "3" :b "4"} {:a "5" :b "6"}]}
      desired-output {:a :1 :b "2" :c [{:a :3 :b "4"} {:a :5 :b "6"}]}
      FIND-KEYS      (recursive-path [] p (cond-path map? (continue-then-stay [MAP-VALS p])
                                                     vector? [ALL p]
                                                     STAY))]

    (clojure.test/is
        (= (transform [FIND-KEYS (must :a)] keyword input)
           desired-output)))

Answer 2

Not a Specter solution, but it is easily done via clojure.walk/postwalk :

(ns demo.core
  (:require
    [clojure.walk :as walk] ))

(def data    {:a "1" :b "2" :c [{:a "3" :b "4"} {:a #{7 8 9} :b "6"}]})
(def desired {:a :1  :b "2" :c [{:a :3  :b "4"} {:a #{7 8 9} :b "6"}]})

(defn transform
  [form]
  (if (map-entry? form)
    (let [[key val] form]
      (if (and
            (= :a key)
            (string? val))
        [key (keyword val)]   ; can return either a 2-vector
        {key val}))           ; or a map here
    form))

(walk/postwalk transform data) => 

    {:a :1, :b "2", :c [{:a :3, :b "4"} {:a #{7 9 8}, :b "6"}]}

I even put in a non-string for one of the :a values to make it trickier.