dedupe.clj

  (def imgs [{:url "http://media.vanityfair.com/photos/55f700a1fad0d98d444d2531/master/w_690/Pandora_VF_690x460_Girl3_2.jpg"} {:url "http://media.vanityfair.com/photos/55f7002c200c34353591cd5d/master/w_690/Pandora_VF_690x460_Girl3_1.jpg"} 
             {:url "http://media.vanityfair.com/photos/55f7002c200c34353591cd5a/master/w_690/Pandora_VF_690x460_Girl3_2.jpg"}])
  (defn remove-dups
    [images]
    (:images (reduce (fn [results image]
                        (let [filename (last (clojure.string/split (:url image) #"\/"))]
                          ;; If we've already seen this filename.
                          (if (contains? (:filenames results) filename)
                            ;; Just return results
                            results
                            ;; Otherwise, add the filename to filenames and the image to images
                            {:images (conj (:images results) image)
                               :filenames (conj (:filenames results) filename)})
                            ))
                        ;; Our starting data, is no images and no filenames
                        {:images [] :filenames #{}}
                        images)
      )
    )
  (remove-dups imgs)