Hi Leon, If you use merge a lot, check out data.int-map <https://github.com/clojure/data.int-map>, it only supports integer keys, but is optimized for merges.
Merge is essentially (reduce conj) so you could see if using a transient <http://clojure.org/transients> version of the original map and merging into it works for you. ~M On Fri, Jun 12, 2015 at 4:20 AM, Leon Grapenthin <grapenthinl...@gmail.com> wrote: > If I want merge in an algorithm where it is often the case that the new > map has the same keys as the old map, I'd assume using the new map as a > replacement is faster in those cases. > > Of course comparing the keys costs and I'd like to know which is the > fastest way. > > Can I do (= (keys old-map) (keys new-map)) or are the orders not > guaranteed? > > I see an alternative in (every? new-map (keys old-map)) which would also > account for cases where the keysets are different but old-map would be > completely replaced by the merge. > > Which one would you recommend, performance wise? > > On a side note: I noticed Clojures merge merges a map onto nil by > replacing nil with an empty map. Wouldn't it be faster if it returned the > map right away? Should I write a ticket? > > Kind regards, > Leon. > > -- > 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. > -- -Mohit Thatte -- 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.
