clojure.core/some-fn

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Type: function Added: Clojure 1.3 Examples: 4 Runnable: 2

([p] [p1 p2] [p1 p2 p3] [p1 p2 p3 & ps])

Takes a set of predicates and returns a function f that returns the first logical true value returned by one of its composing predicates against any of its arguments, else it returns logical false. Note that f is short-circuiting in that it will stop execution on the first argument that triggers a logical true result against the original predicates.

Examples

by replore on 2011-11-15 ▶

((some-fn even?) 1) false ((some-fn even?) 2) true ((some-fn even?) 1 2) true

by uvtc on 2012-07-31 ▶

;; `some-fn` is useful for when you'd use `some` (to find out if any ;; values in a given coll satisfy some predicate), but have more than ;; one predicate. For example, to check if any values in a coll are ;; either even or less than 10: (or (some even? [1 2 3]) (some #(< % 10) [1 2 3])) ;; but `some-fn` can save you some duplication here: ((some-fn even? #(< % 10)) 1 2 3) ;; Minor note: the former returns nil if it doesn't find ;; what it's looking for. The latter returns false.

by ryo on 2014-05-10 . May have evaluation errors. ▶

;;; http://en.wikipedia.org/wiki/Fizz_buzz (def fizzbuzz (some-fn #(and (= (mod % 3) 0) (= (mod % 5) 0) "FizzBuzz") #(and (= (mod % 3) 0) "Fizz") #(and (= (mod % 5) 0) "Buzz") str)) (run! println (map fizzbuzz (range 1 18))) 1 2 Fizz 4 Buzz Fizz 7 8 Fizz Buzz 11 Fizz 13 14 FizzBuzz 16 17

by bkovitz on 2016-04-28 . May have evaluation errors. ▶

;; Here's an easy way to apply several functions in succession to the same ;; value and get the first true result. Note the double parentheses at the ;; beginning: because some-fn returns a function, you have to apply it. ((some-fn :a :b :c :d) {:c 3 :d 4}) ;=> 3 ;; Here's how to do the same thing but with a vector of functions. Note ;; the 'apply' as well as the double parentheses, since you have to make ;; some-fn take its arguments from the vector. (def parsers [parse-custom-command parse-basic-command parse-weird-command reject-command]) ((apply some-fn parsers) text-from-user) ;; Each element of parsers is a function that returns a data structure if ;; it successfully parses its argument or nil if it fails. reject-command ;; always succeeds, returning a representation of an error. ;; Note the technique of putting a catch-all function for errors last.

See also

• clojure.core/every-pred (2)
• clojure.core/some (15)
• clojure.core/some-> (0)
• clojure.core/some->>
• clojure.core/or (2)
• clojure.core/fnil (1)

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