Thanks for clearing that up. -Andres
On Sunday, August 5, 2018 at 12:17:47 AM UTC-7, Andy Fingerhut wrote: > > Except for sorted-map and a few other special kinds of maps with ordering > guarantees, the normal kind of map in Clojure is a hash-map, which uses a > hash function of the keys to create a tree data structure with the hash > value as a search key. seq on hash-map's traverses these trees in a > deterministic order, so the return order of keys from the clojure.core/keys > or clojure.core/seq functions are in increasing order of hash value of the > keys (or maybe it is decreasing -- either way, it is independent of the > order that you added the keys to the map). > > For memory and run-time efficiency, maps that have 8 or fewer keys in them > are implemented with a different concrete data structure called > array-map's. Those do happen to give you back the elements in the order > that the keys were first added, but as soon as you add a 9th key, the > implementation switches to a hash-map, and the order is then unrelated to > the order that keys were added. > > If you want a map that is guaranteed to return the keys in the order they > were added, there is an implementation of this available called > ordered-maps's here: https://github.com/amalloy/ordered > > Andy > > On Sun, Aug 5, 2018 at 12:12 AM Andres Pineda <humb....@gmail.com > <javascript:>> wrote: > >> Why does the keys function return unexpected order when there are 8 or >> more keys in a map? >> >> I believe the order issue also applies to seq. >> >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clo...@googlegroups.com >> <javascript:> >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+u...@googlegroups.com <javascript:> >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to clojure+u...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
