[clean-list] Can anyone improve this program?

[Peter Achten]

Dear Jigang,

If you don't mind an additional class restriction on your function (viz. 
Ord), then the following also works:

import StdEnv

Start = count [5,6,5,7,5,6]

count :: [a] -> [(a,Int)] | Ord, Eq a
count xs = map (\xs -> (hd xs,length xs)) (group (sort xs))

group :: [a] -> [[a]] | Eq a
group []     = []
group [x:xs] = [[x:eq_x]:group uneq_x]
where
     (eq_x,uneq_x)   = span ((==) x) xs

Regards,
Peter

At 01:33 AM 7/10/2005, you wrote:
>Hi Nick,
>
>Thank you for your email.
>
>What I want to do is to get the occurences of a element in a list, e.g. 
>[5,6,5,7,5,6] => [(5,3),(6,2)(7,1)], without using a extra parameter like 
>n in (count n list).
>
>I prefer
>Start = count [5,6,5,7,5,6]
>than
>
>Start = count n [5,6,5,7,5,6]
>
>How do you think about the next generation language, FP or OOP?
>
>Thank again.
>
>Jigang
>
>
>
>
>
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