Filter nil values from Clojure map?

Question

What is the best way to filter nil values from a Clojure map {}?

{ :a :x :b nil :c :z }
;;=>  { :a :x, :c :z }

Answer 1

I would use:

(into {} (filter (comp some? val) {:a :x, :b nil, :c :z}))

=> {:a :x, :c :z}

Doing the some? check explicitly is important because if you just do (into {} (filter val {...})) then you will erroneously remove values that are boolean false.