That's the beauty of this language - there are many ways to skin the cat!
Here's a version using reduce...
(defn filt-split [pred col]
(reduce (fn [[a b] x] (if (pred x) [(conj a x) b] [a (conj b x)]))
[[] []] col))
(filt-split even? [1 2 3 4 5 6 7 8])
[[2 4 6 8] [1 3 5 7]]
But when you look at separate in clojure.contrib.seq-utils its simple
and elegant;
(defn separate [f s]
[(filter f s) (filter (complement f) s)])
Rgds, Adrian.
On Sun, Mar 8, 2009 at 6:44 AM, e <evier...@gmail.com> wrote:
> check the discussion with the subject, "time lies, even with doall". We
> came up with something like the following, but some name change change
> tweaks were suggested. This thing takes a pred and a collection and returns
> a list of two collections -- one that passes the pred, and one that fails.
>
> (defn filt-rem [pred coll]
> (loop [l1 () l2 () [f & r] coll]
> (if f
> (if (pred f)
> (recur (conj l1 f) l2 r)
> (recur l1 (conj l2 f) r))
> (list l1 l2))))
>
>
> On Sat, Mar 7, 2009 at 11:37 PM, Jeffrey Straszheim
> <straszheimjeff...@gmail.com> wrote:
>>
>> There is separate in seq_utils in contrib.
>>
>> On Sat, Mar 7, 2009 at 11:29 PM, David Sletten <da...@bosatsu.net> wrote:
>>>
>>> I'm reading the Sequences chapter of Programming Clojure, and Stu
>>> points out that split-with combines the semantics of take-while and
>>> drop-while. But is there a function that does something similar with
>>> "filter"? Namely, rather than simply filtering the elements of a
>>> collection that satisfy a predicate I also want to capture those that
>>> don't. Something like this:
>>> (defn filter-split [pred coll]
>>> (loop [trues '() falses '() coll coll]
>>> (cond (empty? coll)
>>> (vector (reverse trues) (reverse falses))
>>> (pred (first coll))
>>> (recur (cons (first coll) trues) falses (rest coll))
>>> :else
>>> (recur trues (cons (first coll) falses) (rest coll)))))
>>>
>>> (filter-split #{\a\e\i\o\u} "is this not pung?") => [(\i \i \o \u)
>>> (\s \space \t \h \s \space \n \t \space \p \n \g \?)]
>>> (filter-split even? (range 10)) => [(0 2 4 6 8) (1 3 5 7 9)]
>>>
>>> Aloha,
>>> David Sletten
>>>
>>>
>>
>>
>>
>
>
> >
>
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