(project xrel ks)
Returns a rel of the elements of xrel with only the keys in ks
;; `project` strips out unwanted key/value pairs from a set of maps.
;; Suppose you have these descriptions of cows:
user=> (def cows #{ {:name "betsy" :id 33} {:name "panda" :id 34} })
#'user/cows
;; You care only about the names. So you can get them like this:
user=> (project cows [:name])
#{{:name "panda"} {:name "betsy"}}
;; also worked from vector of maps.
user=> (def sample [{:name "Minsun" :device "iphone6"}
{:name "hogle" :device "iphone7 matte black"}])
;;=> #'user/sample
user=> (clojure.set/project sample [:name])
;;=> #{{:name "hogle"} {:name "Minsun"}}