(count even? [1 2 3 4 5]) # => 2 (count (fn [x] (> x 3)) [1 2 3 4 5]) # => 2 (count |(> $ 3) [1 2 3 4 5]) # => 2 (count (fn [x] (truthy? x)) [nil false true 42 :a "foo"]) # => 4 (count |(truthy? $) [nil false true 42 :a "foo"]) # => 4 (var f even?) (count f [1 2 3 4 5]) # => 2 (set f odd?) (count f [1 2 3 4 5]) # => 3 (map (fn [f] (count f [1 2 3 4 5])) [even? odd?]) # => @[2 3] (map |(count $ [1 2 3 4 5]) [even? odd?]) # => @[2 3]