On Thu, Aug 26, 2010 at 11:53 AM, Chouser <chou...@gmail.com> wrote: > On Thu, Aug 26, 2010 at 9:44 AM, Jon Seltzer <seltzer1...@gmail.com> > wrote: > > I know what assoc does: > > > > user=> (assoc [\a \b \c] 0 \d) ;please extend to much larger vector > > with index somewhere in the middle > > [\d \b \c] > > > > but what if I want: > > > > user=> (assoc-x [\a \b \c] 0 \d) ;is there an assoc-x > > [\a \d \b \c] > > > > I don't see a function that does this. I'm sure I'm missing it. I, > > of course, know this could be done with a combination of other > > functions like subvec and/or into but it seems fundamental enough to > > have its function. > > The internal structure of vectors is such that this cannot be > done efficiently, which is why no function to do it is included > in clojure.core. You can do it inefficiently like this: > > (let [v '[a b c d e f] > i 3] > (into (subvec v 0 i) (cons 'X (subvec v i)))) > ;=> [a b c X d e f] > > That's about as good as you're going to get with vectors, O(n) > where n is (- (count v) i). > > --Chouser > http://joyofclojure.com/
How is the performance of your FingerTrees looking? ;) David -- 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
