clojure.core/min-key

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Type: function Added: Clojure 1.0 Examples: 3 Runnable: 3

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

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

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

Examples

by lozh on 2010-07-24 ▶

;; we have a list of key colours ;; We want to find the one closest to a supplied colour ;; We're storing rgb values as [r g b] ;; use min-key to find colour that minimizes ;; the euclidean distance between the supplied colour ;; and each key colour ;; thanks to rhudson, raek and mfex on #clojure (defn distance-squared "Euclidean distance between two collections considered as coordinates" [c1 c2] (->> (map - c1 c2) (map #(* % %)) (reduce +))) (def key-colours {[224 41 224] :purple [24 180 46] :green [12 129 245] :blue [254 232 23] :yellow [233 233 233] :white [245 27 55] :red [231 119 41] :orange }) (defn rgb-to-key-colour "Find colour in colour map closest to the supplied [r g b] triple" [rgb-triple colour-map] (colour-map (apply min-key (partial distance-squared rgb-triple) (keys colour-map)))) (rgb-to-key-colour [255 0 0] key-colours) :red

by jamesqiu on 2011-07-24 ▶

; "min-key"/"max-key" to "min"/"max" like "sort-by" to "sort" (min-key #(Math/abs %) -3 1 4) ; 1 (apply min-key #(Math/abs %) [-3 1 4]) ; 1

by guillaume on 2020-06-29 ▶

(min-key second ["Jon" 1] ["Rich" 6] ["Nancy" 3]) ["Jon" 1]

See also

• clojure.core/min (2)
• clojure.core/max-key (5)

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