Weird order in sets in Clojure

Question

So, I\'m trying to work my way through Brave Clojure. The third exercise consists on creating a map function but instead of returning a list it should return a set. OK, so there

Answer 1

Sets are by default unordered. Therefore your results are fine, they contain the right elements. In general order is not important for sets.

Answer 2

As ymonad said, Clojure sets are "randomly" ordered:

> (println #{ 1 2 3 4 5 } )
#{1 4 3 2 5}

The literal set syntax #{1 2 3 4 5} is just short for (hash-set ...). You can get a sorted set as shown:

> (hash-set 1 2 3 4 5 6)
#{1 4 6 3 2 5}
> (sorted-set 1 2 3 4 5 6)
#{1 2 3 4 5 6}
> (into (sorted-set) #{1 2 3 4 5 6} )
#{1 2 3 4 5 6}

In the last example, we use into to add elements from the regular set into an empty sorted-set