Hi Mark, The results will depend on the objects you are comparing. If you need to search through the list multiple times, converting to a set once is almost certainly going to be faster. But, if you're just doing it once, iterating will usually be much faster:
user> (time (dotimes [_ 100000] (contains? (set (range 100)) 10))) "Elapsed time: 7708.336 msecs" user> (time (dotimes [_ 100000] (some #(= 10 %) (range 100)))) "Elapsed time: 291.474 msecs" user> (time (let [s (set (range 100))] (dotimes [_ 100000] (contains? s 10)))) "Elapsed time: 27.978 msecs" In a simple test I get similar results for strings too... what conditions were you testing under? -Jason On Feb 26, 7:53 am, Mark Volkmann <r.mark.volkm...@gmail.com> wrote: > I thought for sure it would be faster to use "some" to determine > whether an item was in a list rather than convert the list to a set > and then use "contains?", but it turns out I was wrong. The latter > approach takes about 1/3 to 1/2 the time! This is the case even when > the list contains 100 items. Of course I realize that if this is a > commonly needed operation for a particular collection, it's better to > use a set instead of a list in the first place. > > (def stooges (list "Moe" "Larry" "Curly")) > (time (some #(= % "Curly") stooges)) > (time (contains? (set stooges) "Curly")) > > -- > R. Mark Volkmann > Object Computing, Inc. --~--~---------~--~----~------------~-------~--~----~ 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 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 -~----------~----~----~----~------~----~------~--~---
