Copyright | (c) Volodymyr Yashchenko |
---|---|

License | BSD3 |

Maintainer | ualinuxcn@gmail.com |

Stability | Unstable |

Portability | portable |

Safe Haskell | Safe |

Language | Haskell2010 |

Library provides functions to find unique and duplicate elements in the list. Unlike Unique or UniqueStrict modules this one uses Data.HashMap.Strict for calculation.

The elements in the list can be unsorted (do not have an instance of Ord class, but Hashable is needed). This implementation is good for ByteStrings.

- isUnique :: (Hashable a, Eq a) => a -> [a] -> Maybe Bool
- isRepeated :: (Hashable a, Eq a) => a -> [a] -> Maybe Bool
- removeDuplicates :: (Hashable a, Eq a) => [a] -> [a]
- repeated :: (Hashable a, Eq a) => [a] -> [a]
- repeatedBy :: (Hashable a, Eq a) => (Int -> Bool) -> [a] -> [a]
- unique :: (Hashable a, Eq a) => [a] -> [a]
- allUnique :: (Hashable a, Eq a) => [a] -> Bool
- count :: (Hashable a, Eq a) => [a] -> [(a, Int)]
- count_ :: (Hashable a, Eq a) => [a] -> [(a, Int)]

# Documentation

isUnique :: (Hashable a, Eq a) => a -> [a] -> Maybe Bool Source #

`isUnique`

function is to check whether the given element is unique in the list or not.

It returns Nothing when the element does not present in the list. Examples:

isUnique 'f' "foo bar" == Just True isUnique 'o' "foo bar" == Just False isUnique '!' "foo bar" == Nothing

Since 0.4.7.2

isRepeated :: (Hashable a, Eq a) => a -> [a] -> Maybe Bool Source #

`isRepeated`

is a reverse function to `isUnique`

Since 0.4.7.2

removeDuplicates :: (Hashable a, Eq a) => [a] -> [a] Source #

`removeDuplicates`

removes the duplicates of elements. Example:

removeDuplicates "foo bar" == " abrfo"

repeated :: (Hashable a, Eq a) => [a] -> [a] Source #

`repeated`

finds only the elements that are present more than once in the list. Example:

repeated "foo bar" == "o"

repeatedBy :: (Hashable a, Eq a) => (Int -> Bool) -> [a] -> [a] Source #

The `repeatedBy`

function behaves just like `repeated`

, except it uses a user-supplied equality predicate.

repeatedBy (>2) "This is the test line" == " stei"

unique :: (Hashable a, Eq a) => [a] -> [a] Source #

`unique`

gets only unique elements, that do not have duplicates.

unique "foo bar" == " abrf"

allUnique :: (Hashable a, Eq a) => [a] -> Bool Source #

`allUnique`

checks whether all elements of the list are unique

allUnique "foo bar" == False allUnique ['a'..'z'] == True allUnique [] == True (!)

Since 0.4.7.2