Udo Stenzel wrote:
That raises the question: Should combining functions on containers be
provided in a strict variant? Should strict application be the default?
With the exception of lists, I generally tend to want strict behavior
for collections. Combined with the principle of least
Scherrer, Chad wrote:
Sorry to drag this thread out, but here's one more thing you might
try...
(This is the café, isn't it? :-)
Another option is perhaps to pack both char and count in one Int and use
some kind of Set.
This should save some space, and possibly time as well (presuming
On Thursday 27 October 2005 10:29, Ketil Malde wrote:
Scherrer, Chad wrote:
Sorry to drag this thread out, but here's one more thing you might
try...
(This is the café, isn't it? :-)
Another option is perhaps to pack both char and count in one Int and
use some kind of Set.
This should
Two solutions using immutable and mutable arrays and no unsafe operations:
module Main where
import Control.Monad.ST
import Data.Ix
import Data.Array
import Data.Array.MArray
import Data.Array.ST
-- using immutable arrays
hist1 :: String - Array Char Int
hist1 str = accumArray (+) 0
Pedro Baltazar Vasconcelos wrote:
Two solutions using immutable and mutable arrays and no unsafe operations:
Both solutions certainly count as nice, but both exhibit an ugly memory
leak. As usual, this is due to too much laziness: no intermediate
result is ever evaluated until it is too late.
Sorry to drag this thread out, but here's one more thing you might
try...
I was thinking, if we just wanted something like
intTable :: [Int] - [(Int, Int)]
we could just replace Map with IntMap in the previous solution:
intTable xs = IntMap.assocs $! foldl' f IntMap.empty xs
where f m x =
Hello, I need to calculate the frequency of each character in a String. And
if I can do this really well in C, I dont find a nice (and fast) answer in
haskell. I tried several functions, listed below, and even the fastest do a
lot of unnecessary things :
calc :: String - [ (Char, Int) ]
--
On 10/25/05, Charles SDudu [EMAIL PROTECTED] wrote:
Hello, I need to calculate the frequency of each character in a String. And
if I can do this really well in C, I dont find a nice (and fast) answer in
haskell. I tried several functions, listed below, and even the fastest do a
lot of
On 2005-10-25 at 12:20+0200 Lemmih wrote:
On 10/25/05, Charles SDudu [EMAIL PROTECTED] wrote:
Hello, I need to calculate the frequency of each
character in a String. And if I can do this really well
in C, I dont find a nice (and fast) answer in haskell. I
tried several functions, listed
On Tuesday 25 Oct 2005 10:40 am, Charles SDudu wrote:
Hello, I need to calculate the frequency of each character in a String.
Something like this maybe (untested code ahead)..
import Data.COrdering
import Data.Tree.AVL
calc :: String - [(Char,Int)]
calc cs = asListL (genAsTree cc [(c,1) | c -
It seems like the fastest way to build a list of frequency from a string is
this :
import Data.Array (assocs, accumArray, Array)
frequency :: String - [(Char,Int)]
frequency = filter (\f - snd f0) . assocs . accumArray (+) 0 ('\0',
'\255') . map (\x-(x,1))
-- (~1.3 sec on a string of 700ko)
On 10/25/05, Charles SDudu [EMAIL PROTECTED] wrote:
It seems like the fastest way to build a list of frequency from a string is
this :
import Data.Array (assocs, accumArray, Array)
frequency :: String - [(Char,Int)]
frequency = filter (\f - snd f0) . assocs . accumArray (+) 0 ('\0',
'\255')
Sebastian Sylvan wrote:
Also, you may use STArrays (I think they come in unboxed as well) for
stateful code, which may be even faster (unless accumArray does some
neat trick to make it O(m) where m is the number of index/value
pairs).
The whole idea with having accumArray as part of the Array
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