Clojure Programming/Examples/API Examples/Hash-map tools

get user=> (get {:a 1, :b 2} :a) 1 ;get also accepts an optional third argument, ;which is returned if key is not found in map: user=> (get {:a 1, :b 2} :e 0) 0 ;maps are functions of their keys, they delegate to get: user=> ({:a 1, :b 2, :c 3} :a) 1 ;and keys likewise user=> (:b {:a 1, :b 2} 99) 2 assoc-in (def nested-structure { :level 0, :nested1 { :level 1, :nested2 { :level 2, :final-data "initial data"}}}) user=> (assoc-in nested-structure [:nested1 :nested2 :final-data] "new data") {:level 0, :nested1 {:nested2 {:level 2, :final-data "new data"}, :level 1}} merge Combine two maps into a more massive map (merge {:a 1} {:b 2}) => {:a 1, :b 2}) (merge-with + {:a 1} {:a 2, :b 3}) => {:a 3 :b 3}