Most Clojure collections cache their hashcode, so that improves things quite bit. Also, very large collections are rarely used as *keys* in other maps. Most of the time key collections are one or two values. This means that what we're really talking about is combining the hash values of a few values, and that's pretty fast.
So sure, the initial hash of one million symbols inside a vector may take a fair amount of time, but I've never seen that in the wild. Timothy On Thu, Nov 9, 2017 at 10:08 PM, Jay Porcasi <jaygporc...@gmail.com> wrote: > i would love to know in a bit more detail how Clojure manages to allow > arbitrary data structures as keys for its immutable hashmaps > hashing an atomic value as a string or number is fast and i see how that > would work when atomic values are used as keys > but how about using a big nested vector as a key? wouldn't hashing it take > an unacceptable amount of time? > yet Clojure manages to do just that and i wonder how > thank you for any bit of clarification > Jay > > -- > 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. > -- “One of the main causes of the fall of the Roman Empire was that–lacking zero–they had no way to indicate successful termination of their C programs.” (Robert Firth) -- 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.
