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| From | Paul Rubin <no.email@nospam.invalid> |
| Newsgroups | comp.lang.forth |
| Subject | Re: :Re: My LOOP is ugly |
| Date | Tue, 29 Nov 2016 23:31:10 -0800 |
| Organization | A noiseless patient Spider |
| Lines | 31 |
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| References | <o1h2gm$qse$1@gioia.aioe.org> <20161130063555.3d621465@maxa-pc> |
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Melzzzzz <mel@zzzzz.com> writes:
> Haskell:
> ....
> p2b = let f :: [(a,b)] -> (a,[b])
> f x = foldl (\(a,b) (_,y) -> (a,y:b)) (fst.head $ x,[snd.head $ x]) (tail x)
> in map (\x->(fst $ f x,sort.snd $ f x))
> . groupBy (\x y-> fst x == fst y ) . sort
> ...
{-# LANGUAGE TransformListComp #-}
import GHC.Exts (sortWith, groupWith, the)
import Data.Char (toUpper)
import Data.Function (on)
p2b xs = [ (the a, b) | (a,b) <- xs
, then sortWith by b
, then group by a using groupWith
]
t1 = [('C',3),('A',1),('B',2),('A',2),('C',2)]
t2 = [("bar",44),("Foo",2),("foo",22),("BAR",4)]
main = do
print . p2b $ t1
print . p2b $ [(map toUpper a, b) | (a,b) <- t2]
================================================================
*Main Prelude> main
[('A',[1,2]),('B',[2]),('C',[2,3])]
[("BAR",[4,44]),("FOO",[2,22])]
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:Re: My LOOP is ugly "Robert L." <No_spamming@noWhere_7073.org> - 2016-11-28 10:56 +0000
Re: :Re: My LOOP is ugly trans <transfire@gmail.com> - 2016-11-28 06:37 -0800
Re: :Re: My LOOP is ugly Melzzzzz <mel@zzzzz.com> - 2016-11-30 06:35 +0100
Re: :Re: My LOOP is ugly Paul Rubin <no.email@nospam.invalid> - 2016-11-29 23:31 -0800
Re: :Re: My LOOP is ugly Melzzzzz <mel@zzzzz.com> - 2016-11-30 08:59 +0100
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