Jarkko Oranen <chous...@gmail.com> writes: > On Jul 15, 1:54 pm, Jan Rychter <j...@rychter.com> wrote: >> I've been looking for a function that would take a seq and create a list >> (a real clojure.lang.PersistentList), but haven't found one. The closest >> I got was: >> >> (apply list my-seq) >> >> Essentially, I'm looking for something similar to (vec) that returns >> lists. >> >> --J. > > Why would you want to do this? Seqs are nearly identical to lists (The > only difference I can think being that lists are Counted, while seqs > are not). If it's about forcing strictness, You can use 'doall.
I rely heavily on count being O(1). I have stacks implemented on top of lists and if those lists turn into seqs, the performance impact is huge. > However, if you really do need a PersistentList, then (apply list the- > seq) is what you need. The vec function is a shortcut for (apply > vector the-seq), provided in the standard library because vectorising > a seq is rather common. Based on my (admittedly limited) experiments with a profiler, apply seems to be a rather heavyweight tool. And vec doesn't seem to be a shortcut for apply, it seems it creates the structure directly: (defn vec "Creates a new vector containing the contents of coll." ([coll] (. clojure.lang.LazilyPersistentVector (createOwning (to-array coll))))) --J. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
