diff --git a/Data/List/Unique.hs b/Data/List/Unique.hs new file mode 100644 --- /dev/null +++ b/Data/List/Unique.hs @@ -0,0 +1,69 @@ +----------------------------------------------------------------------------- +-- | +-- Module : Data.List.Unique +-- Copyright : (c) Volodymyr Yaschenko +-- License : BSD3 +-- +-- Maintainer : ualinuxcn@gmail.com +-- Stability : Unstable +-- Portability : portable +-- +----------------------------------------------------------------------------- + +module Data.List.Unique + (sortUniq + , repeated + , unique + , count + , count_ + , countElem + ) where + +import Data.List (sort,group,nub,filter,map,length) +import Prelude hiding (map,filter,length) + +-- | 'sortUniq' sorts the list and removes the duplicates of elements. Example: +-- +-- sortUniq "foo bar" == " abfor" + +sortUniq :: Ord a => [a] -> [a] +sortUniq = nub . sort + +filterByLength :: Ord a => (Int -> Bool) -> [a] -> [[a]] +filterByLength p = filter (p . length) . group . sort + +-- | 'repeated' finds only the elements that are present more than once in the list. Example: +-- +-- repeated "foo bar" == "o" + +repeated :: Ord a => [a] -> [a] +repeated = map head . filterByLength (>1) + +-- | 'unique' gets only unique elements, those that do not have duplicates. +-- It sorts them. Example: +-- +-- unique "foo bar" == " abfr" + +unique :: Ord a => [a] -> [a] +unique = concat . filterByLength (==1) + +-- | 'count' the elements in the list, sorts by keys (elements). Example: +-- +-- count "foo bar" == [(' ',1),('a',1),('b',1),('f',1),('o',2),('r',1)] + +count :: Ord a => [a] -> [(a, Int)] +count = map (\x -> (head x,length x)) . group . sort + +-- | 'count_' the elements in the list, sorts by values. Example: +-- +-- count_ "foo bar" == [(' ',1),('a',1),('b',1),('f',1),('r',1),('o',2)] + +count_ :: Ord a => [a] -> [(a, Int)] +count_ = map (\(x,y) -> (y,x)) . sort . map (\x -> (length x,head x)) . group . sort + +-- | 'countElem' gets the amount of occurrences of the specified element. Example: +-- +-- countElem 'o' "foo bar" == Just 2 + +countElem :: Ord a => a -> [a] -> Maybe Int +countElem x = lookup x . count diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,30 @@ +Copyright (c) 2014, Volodymyr Yaschenko + +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following + disclaimer in the documentation and/or other materials provided + with the distribution. + + * Neither the name of Volodymyr Yaschenko nor the names of other + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/Unique.cabal b/Unique.cabal new file mode 100644 --- /dev/null +++ b/Unique.cabal @@ -0,0 +1,67 @@ +-- Initial Unique.cabal generated by cabal init. For further +-- documentation, see http://haskell.org/cabal/users-guide/ + +-- The name of the package. +name: Unique + +-- The package version. See the Haskell package versioning policy (PVP) +-- for standards guiding when and how versions should be incremented. +-- http://www.haskell.org/haskellwiki/Package_versioning_policy +-- PVP summary: +-+------- breaking API changes +-- | | +----- non-breaking API additions +-- | | | +--- code changes with no API change +version: 0.1.0.0 + +-- A short (one-line) description of the package. +synopsis: Provides with the functionality like unix "uniq" utility + +-- A longer description of the package. +description: Module provides with functions to find unique and duplicate elements in the list + +-- The license under which the package is released. +license: BSD3 + +-- The file containing the license text. +license-file: LICENSE + +-- The package author(s). +author: Volodymyr Yaschenko + +-- An email address to which users can send suggestions, bug reports, and +-- patches. +maintainer: ualinuxcn@gmail.com + +-- A copyright notice. +-- copyright: + +category: Data + +build-type: Simple + +-- Extra files to be distributed with the package, such as examples or a +-- README. +-- extra-source-files: + +-- Constraint on the version of Cabal needed to build this package. +cabal-version: >=1.10 + + +library + -- Modules exported by the library. + exposed-modules: Data.List.Unique + + -- Modules included in this library but not exported. + -- other-modules: + + -- LANGUAGE extensions used by modules in this package. + -- other-extensions: + + -- Other library packages from which modules are imported. + build-depends: base >=4.7 && <4.8 + + -- Directories containing source files. + -- hs-source-dirs: + + -- Base language which the package is written in. + default-language: Haskell2010 +