Lodash _.pluck does this

var users = [
  { 'user': 'barney', 'age': 36 },
  { 'user': 'fred',   'age': 40 }
];

_.pluck(users, 'user');
// → ['barney', 'fred']

Good thing about it is it can also go deep like this:

var users = [
  { 'user': {name: 'barney'}, 'age': 36 },
  { 'user': {name: 'fred'},   'age': 40 }
];

_.pluck(users, 'user.name');
// ["barney", "fred"]

Is there equivalent in Clojure core of this? I mean, I can easily create one line somewhat like this

(defn pluck
  [collection path]
  (map #(get-in % path) collection))

And use it like this:

(def my-coll [{:a {:z 1}} {:a {:z 2}}])
(pluck my-coll [:a :z])
=> (1 2)

I was just wondering if there's such thing already included in Clojure and I overlooked it.

Lodash _.pluck does this

var users = [
  { 'user': 'barney', 'age': 36 },
  { 'user': 'fred',   'age': 40 }
];

_.pluck(users, 'user');
// → ['barney', 'fred']

Good thing about it is it can also go deep like this:

var users = [
  { 'user': {name: 'barney'}, 'age': 36 },
  { 'user': {name: 'fred'},   'age': 40 }
];

_.pluck(users, 'user.name');
// ["barney", "fred"]

Is there equivalent in Clojure core of this? I mean, I can easily create one line somewhat like this

(defn pluck
  [collection path]
  (map #(get-in % path) collection))

And use it like this:

(def my-coll [{:a {:z 1}} {:a {:z 2}}])
(pluck my-coll [:a :z])
=> (1 2)

I was just wondering if there's such thing already included in Clojure and I overlooked it.

• javascript
• clojure
• lodash

5 Answers 5

There is no built-in function for this. You can refer to clojure.core API reference and the cheatsheet to look up what's available.

I would say Clojure's syntax is light enough that it feels sufficient to use a bination of map and an accessor utility like get-in.

This also demonstrates a well-adopted principle in Clojure munity: provide mostly simple defaults and let the users pose them as they need. Some people would probably argue that pluck conflates iteration and querying.

The most simple way is something like:

(map #(:user %) users)

It will return list '(36 40)

Here are simple tricks:

(def my-coll [{:a {:z 1}} {:a {:z 2}}])

(map :a my-coll)
 => ({:z 1} {:z 2})

(map (p :z :a) my-coll)
 => (1 2)

Works because keyword behaves like a function as well.

lodash deprecated _.pluck function in favor of _.map. Thus:

_.pluck(users, 'user')

is now

_.map(users, 'user')

I like the lodash/fp flavor, wich put the iteratees in front of the collection

_.map('user', users)

You also get autocurry for free

_.map('user')(users)

This function in lodash is now called pick and I believe its closest equivalent in Clojure is select-keys.