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Programming-Idioms

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  • C++

Idiom #222 Find the first index of an element in list

Set i to the first index in list items at which the element x can be found, or -1 if items does not contain x.

auto it = std::find(items.begin(), items.end(), x);
i = it == items.end() ? std::distance(items.begin(), it) : -1;
(defn find-index [x items]
  (or (->> items
           (map-indexed vector)
           (filter #(= x (peek %)))
           ffirst)
      -1))

New implementation...
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