Enumerate over a sequence in Clojure?

clojure enumeration

davidscolgan · Nov 16, 2010 · Viewed 7.1k times · Source

In Python I can do this:

animals = ['dog', 'cat', 'bird']
for i, animal in enumerate(animals):
    print i, animal

Which outputs:

0 dog
1 cat
2 bird

How would I accomplish the same thing in Clojure? I considered using a list comprehension like this:

(println
  (let [animals ["dog" "cat" "bird"]]
    (for [i (range (count animals))
          animal animals]
      (format "%d %d\n" i animal))))

But this prints out every combination of number and animal. I'm guessing there is a simple and elegant way to do this but I'm not seeing it.

Answer

There is map-indexed in core as of 1.2.

Your example would be:

(doseq [[i animal] (map-indexed vector ["dog" "cat" "bird"])]
  (println i animal))