If maplist/tails, why not inits as well? Prelude GOA Data.List> inits [1,2,3] [[],[1],[1,2],[1,2,3]]
I've also found haskell's unfold useful: (defn expand ;; since Clojure has "reduce" and not "foldl" [f seed] (lazy-seq (when-let [[a b] (f seed)] (cons a (expand f b))))) As with maplist it can be implemented in terms of iterate, though I think that implementation is unattractive. (And iterate can be implemented in terms of it), On Sun, Sep 30, 2012 at 7:51 AM, Marc Dzaebel <mdzae...@web.de> wrote: > I often have the need to lazily iterate over rests of lists rather than > elements. I frequently saw discussions about this topic. In CL it's called > maplist, in Haskell it's tails (Scala missing?). Of course there are several > methods to do this, e.g. (take-while identity (iterate next S)), but if you > use them recursivly, code reads badly. So my proposal would be to have a > kind of following function in the core: > > (defn maplist > ([s] (maplist identity s)) > ([f s] (when-let [s (seq s)] (lazy-seq (cons (f s) (maplist f (next > s))))))) > ;(maplist [1 2 3]) -> ((1 2 3) (2 3) (3)) > > Questions: > > Would such a method help more developers? > Is there a conceptional reason, to omit a maplist equivalent in Clojure? > > Thanks, Marc > > -- > 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 -- Ben Wolfson "Human kind has used its intelligence to vary the flavour of drinks, which may be sweet, aromatic, fermented or spirit-based. ... Family and social life also offer numerous other occasions to consume drinks for pleasure." [Larousse, "Drink" entry] -- 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
