clojure.core/max-key

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Type: function Added: Clojure 1.0 Examples: 5 Runnable: 5

([k x] [k x y] [k x y & more])

Returns the x for which (k x), a number, is greatest.

If there are multiple such xs, the last one is returned.

Examples

by pkolloch on 2010-08-20 ▶

(max-key count "asd" "bsd" "dsd" "long word") "long word"

by huahaiy on 2014-12-16 ▶

; find the key that has the highest value in a map (key (apply max-key val {:a 3 :b 7 :c 9})) :c

by garaud on 2020-05-23 ▶

;; find the index of the highest value. Equivalent to an 'argmax' function (first (apply max-key second (map-indexed vector '(2 1 6 5 4)))) 2

by sova on 2021-04-01 ▶

;; find the max :timestamp in a collection of maps. (def mmm [ {:timestamp 1 :name "v"} {:timestamp 2 :name "q"} {:timestamp 3 :name "r"}]) (apply max-key :timestamp mmm) {:timestamp 3, :name "r"} (:timestamp (apply max-key :timestamp mmm)) 3 ;;if the map is indexed by item-id, use an anonymous function where the key goes. (def map-with-index { "gary" {:timestamp 1 :name "v"} "carl" {:timestamp 2 :name "q"} "lola" {:timestamp 3 :name "r"}}) (apply max-key #(:timestamp (val %)) map-with-index) ["lola" {:timestamp 3, :name "r"}] ;notice how we replaced :timestamp with #(:timestamp (val %)) ;to get the inner value [and not the (key %)] of the indexed version.

by sofiiahitlan on 2024-07-26 ▶

;; filter out the the biggest map based on the size (def maps [{:a 1 :b 2} {:a 1} {:a 1 :b 2 :c 3} {:a 1 :b 2 :c 3 :d 4}]) (apply max-key count maps) {:a 1 :b 2 :c 3 :d 4} ;; in a case when multiple maps are of the same size, returns the last ;; biggest map it encounters

See also

• clojure.core/max (3)
• clojure.core/min-key (3)
• clojure.core/min (2)

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