在 2011-8-26 下午11:44，"Tassilo Horn" <[email protected]>写道： > > Shouxun Yang <[email protected]> writes: > > > (defn my-flatten > > [coll] > > (loop [acc [] coll coll] > > (if-let [[a & coll] coll] > > (if (or (list? a) (vector? a)) > > (recur acc (if (empty? coll) > > (vec a) > > (conj (vec a) coll))) > > (recur (conj acc a) coll)) > > acc))) > > > > The above code failed the second test: ["a" ["b"] "c"]. > > > > Instead of producing the correct result, it produces: ["a" "b" ("c")]. > > The problem is that in ["a" "b" ("c")], ("c") is neither a list nor a > vector. It's a seq. Unfortunately, seqs and lists have the same print > syntax, so you were not able to easily see that. > > BTW: You should use coll? instead of sequential? or seq? if your > intention is only to check if the thing is some collection. For > example, (sequential? #{1 2 3}) is false. (sequential? only works for > ordered collections like vectors, lists and seqs.)
Thanks. For this case, I actually need an atom? predicate as in CL. > BTW2: Instead of (empty? coll), use the idiomatic (seq coll) recipe. Good point. I read about the tip before, but forgot in my own code. > Bye, > Tassilo -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to [email protected] Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/clojure?hl=en
