Slightly shorter version:
(defn frequencies
"Returns a map from distinct items in coll to the number of
times they appear."
[coll]
(reduce (fn [counts x]
(merge-with + counts {x 1}))
{} coll))
On Dec 11, 9:14 am, Stuart Sierra wr
I've added a slightly modified version to clojure.contrib.seq-utils:
(defn frequencies
"Returns a map from distinct items in coll to the number of times
they appear."
[coll]
(reduce (fn [counts x]
(assoc counts x (inc (get counts x 0
{} coll))
-Stuart Sierra
Yup, five bugs by my count. Not bad for a one-liner. More coffee
necessary.
Same algorithm, but tested.
(defn frequencies [coll]
(reduce (fn [map val] (assoc map val (if (contains? map val) (+ 1
(get map val)) 1))) {} coll)
)
On Dec 11, 9:52 am, Randall R Schulz <[EMAIL PROTECTED]> wro
On Dec 11, 9:21 am, bOR_ <[EMAIL PROTECTED]> wrote:
> I thought I remembered there was a method in the api somewhere that
> would count the frequency of each unique item in a collection, but I
> can't find it anymore. What would be a brief way to write that in
> clojure?
I think what you want is:
On Thursday 11 December 2008 06:33, Dave Griffith wrote:
> On Dec 11, 9:21 am, bOR_ <[EMAIL PROTECTED]> wrote:
> > Hi all,
> >
> > I thought I remembered there was a method in the api somewhere that
> > would count the frequency of each unique item in a collection, but
> > I can't find it anymore.
I don't recall a histogram-like method, though I may just be forgetting.
(defn frequencies [coll]
(reduce
(fn [map val] (assoc map val (inc (get map val 1
{}
coll))
On Thu, Dec 11, 2008 at 9:33 AM, Dave Griffith
<[EMAIL PROTECTED]> wrote:
>
>
> (defn frequencies [coll]
>
(defn frequencies [coll]
(reduce (fn [map val] (assoc map val (if (contains map val)
(get map val) 1)) #{})
)
On Dec 11, 9:21 am, bOR_ <[EMAIL PROTECTED]> wrote:
> Hi all,
>
> I thought I remembered there was a method in the api somewhere that
> would count the frequency of each uniq
Hi all,
I thought I remembered there was a method in the api somewhere that
would count the frequency of each unique item in a collection, but I
can't find it anymore. What would be a brief way to write that in
clojure?
(In ruby: array.inject(Hash.new(0)) {|hash,key| hash[key] += 1 ;
hash})
--
