| Copyright | (c) Gershom Bazerman 2018 |
|---|---|
| License | BSD-style |
| Maintainer | libraries@haskell.org |
| Portability | portable |
| Safe Haskell | Trustworthy |
| Language | Haskell98 |
Data.Containers.ListUtils
Description
This module provides efficient containers-based functions on the list type.
Documentation
nubOrd :: Ord a => [a] -> [a] Source #
\( O(n \log n \). The nubOrd function removes duplicate elements from a list.
In particular, it keeps only the first occurrence of each element. By using a
Set internally it has better asymptotics than the standard nub
function.
Strictness
nubOrd is strict in the elements of the list.
Efficiency note
When applicable, it is almost always better to use nubInt or nubIntOn instead
of this function. For example, the best way to nub a list of characters is
nubIntOn fromEnum xs
nubOrdOn :: Ord b => (a -> b) -> [a] -> [a] Source #
The nubOrdOn function behaves just like nubOrd except it performs
comparisons not on the original datatype, but a user-specified projection
from that datatype.
Strictness
nubOrdOn is strict in the values of the function applied to the
elements of the list.
nubInt :: [Int] -> [Int] Source #
\( O(n \min(n,W)) \). The nubInt function removes duplicate Int
values from a list. In particular, it keeps only the first occurrence
of each element. By using an IntSet internally, it attains better
asymptotics than the standard nub function.
See also nubIntOn, a more widely applicable generalization.
Strictness
nubInt is strict in the elements of the list.