All subsets of a set in clojure

Question

I wish to generate all subsets of a set except empty set

ie

(all-subsets #{1 2 3}) => #{#{1},#{2},#{3},#{1,2},#{2,3},#{3,1},#{1,2,3}}

How can this be done in clojure?

Answer 1

In your :dependencies in project.clj:

[org.clojure/math.combinatorics "0.0.7"]

At the REPL:

(require '[clojure.math.combinatorics :as combinatorics])

(->> #{1 2 3}
  (combinatorics/subsets)
  (remove empty?)
  (map set)
  (set))
;= #{#{1} #{2} #{3} #{1 2} #{1 3} #{2 3} #{1 2 3}}

clojure.math.combinatorics/subsets sensibly returns a seq of seqs, hence the extra transformations to match your desired output.