Hyphenating underscored Clojure map keys for database results

Question

I'm using SQLingvo and clojure.jdbc to access a PostgreSQL database.

Data is being returned as underscored maps, e.g. {:created_at "some date"}, when I expect hyphenated keywords like :created-at. Is there an easy way to marshall these maps back into their hyphenated versions?

score 4 · Answer 1 · answered Sep 11 '14 at 12:43

4

I've used clojure.walk/postwalk to accomplish this.

(defn transform-keys
  "Recursively transforms all map keys in coll with the transform-key fn."
  [transform-key coll]
  (letfn [(transform [x] (if (map? x)
                           (into {} (map (fn [[k v]] [(transform-key k) v]) x))
                           x))]
    (walk/postwalk transform coll)))

The first argument is a function that takes the existing key and returns the new one. In your case, you can convert the keyword to a string, replace the underscores with hyphens, and convert it back into a keyword.

https://gist.github.com/jeremyheiler/fe9256e540121e771285

answered Sep 11 '14 at 12:43

Jeremy

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Nowadays also worth looking at [Specter](https://github.com/nathanmarz/specter) by Nathan Marz. – Petrus Theron Mar 26 '18 at 21:48
Note that this is _very_ similar to `clojure.walk/keywordize-keys` which you can take as an inspiration. – Juraj Martinka Sep 19 '19 at 08:54

score 1 · Answer 2 · answered Mar 02 '19 at 14:15

1

It should be possible to provide {:identifiers #(.replace % \_ \-)} in options when you make a query, just as it is in clojure.java.jdbc.

answered Mar 02 '19 at 14:15

Eugene Pakhomov

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Hyphenating underscored Clojure map keys for database results

2 Answers2