Hi,
Am 09.11.2009 um 07:33 schrieb Wilson MacGyver:
I did search in the API docs for both core and contrib, but didn't
find anything like
it.
Does Clojure have a function like Haskell's group?
In Haskell,
Input: group [1,2,2,1,1,1,2,2,2,1]
Output: [[1],[2,2],[1,1,1],[2,2,2],[1]]
I'm
Meikel,
Is like you over engineered your version?
(defn group
[s]
(lazy-seq
(when-let [s (seq s)]
(let [f(first s)
[fs r] (split-with #(= % f) s)]
(cons fs (group r))
Should be ..
(defn group
[s]
(lazy-seq
(when-let [s (seq s)]
(let [f
Meikel,
What is the gain of using lazy-seq here? Why can't we go without laziness?
(defn group
[s]
(when-let [s (seq s)]
(let [f(first s)
[fs r] (split-with #(= % f) s)]
(cons fs (group r)
Regards,
Emeka
On Mon, Nov 9, 2009 at 4:44 PM, Emeka
On Mon, Nov 09, 2009 at 04:49:16PM +, Emeka wrote:
What is the gain of using lazy-seq here? Why can't we go without laziness?
- The lazy version doesn't consume stack per length of the sequence.
- The lazy version works with unbounded sequences.
For short sequences it probably
Thanks guys for the various solutions. I set out trying to try a recur solution
So I came up with this. the idea is to go through the collection being
passed, and grab one element, then do drop-while until a different
element is encountered. repeat until there is no more left in the collection.
(defn group [x]
(loop [newlist [] currlist x]
(if (not (empty? x))
(recur (newlist (cons (first x) newlist))
(newlist (cons (first x) newlist)) You are making a function call here
using an empty vector and your argument is a list. This is not possible,
that's why you have that error ([] (cons
On Mon, Nov 9, 2009 at 2:31 PM, Emeka emekami...@gmail.com wrote:
(defn group [x]
(loop [newlist [] currlist x]
(if (not (empty? x))
(recur (newlist (cons (first x) newlist))
(newlist (cons (first x) newlist)) You are making a function call here
using an empty vector and your argument
Hi,
Am 09.11.2009 um 20:08 schrieb Wilson MacGyver:
(defn group [x]
(loop [newlist [] currlist x]
(if (not (empty? x))
(recur (newlist (cons (first x) newlist))
(currlist (drop-while #(= (first currlist) %) currlist))
It seems logical to me, but when I tried
Ah that was what I was missing. You are right,
I misunderstood the recur form.
For some reason I thought in recur you have to specify the
name of the variable that it's bound to.
so when I wrote
(recur (newlist (cons (first x) newlist))
I thought I was saying in recur, rebind (cons (first x)
Wilson MacGyver wrote:
Does Clojure have a function like Haskell's group?
In Haskell,
Input: group [1,2,2,1,1,1,2,2,2,1]
Output: [[1],[2,2],[1,1,1],[2,2,2],[1]]
(use 'clojure.contrib.seq-utils)
(partition-by identity [1 2 2 1 1 1 2 2 2 1])
= ((1) (2 2) (1 1 1) (2 2 2) (1))
ah, thank you for the help!
On Mon, Nov 9, 2009 at 1:57 AM, Alex Osborne a...@meshy.org wrote:
Wilson MacGyver wrote:
Does Clojure have a function like Haskell's group?
In Haskell,
Input: group [1,2,2,1,1,1,2,2,2,1]
Output: [[1],[2,2],[1,1,1],[2,2,2],[1]]
(use
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