Portability | H98 |
---|---|
Stability | experimental |
Maintainer | Douglas Burke |
This module defines some generic list and related helper functions.
- select :: (a -> Bool) -> [a] -> [b] -> [b]
- deleteIndex :: [a] -> Int -> [a]
- subset :: Eq a => [a] -> [a] -> Bool
- equiv :: Eq a => [a] -> [a] -> Bool
- addSetElem :: Eq a => a -> [a] -> [a]
- headOrNothing :: [Maybe a] -> Maybe a
- pairUngroup :: (a, [b]) -> [(a, b)]
- pairSort :: Ord a => [(a, b)] -> [(a, b)]
- pairGroup :: Ord a => [(a, b)] -> [(a, [b])]
- breakAll :: (a -> Bool) -> [a] -> [[a]]
- powerSet :: [a] -> [[a]]
- permutations :: [a] -> [[a]]
- listProduct :: [[a]] -> [[a]]
- powerSequencesLen :: Int -> [a] -> [[a]]
- flist :: [a -> b] -> a -> [b]
- allp :: [a -> Bool] -> a -> Bool
- anyp :: [a -> Bool] -> a -> Bool
Documentation
select :: (a -> Bool) -> [a] -> [b] -> [b]Source
Select is like filter, except that it tests one list to select elements from a second list.
deleteIndex :: [a] -> Int -> [a]Source
Delete the n'th element of a list, returning the result
If the list doesn't have an n'th element, return the list unchanged.
addSetElem :: Eq a => a -> [a] -> [a]Source
Add element to set
headOrNothing :: [Maybe a] -> Maybe aSource
Return head of a list of Maybe
's, or Nothing
if list is empty
Use with filter isJust
to select a non-Nothing value from a
list when such a value is present.
pairUngroup :: (a, [b]) -> [(a, b)]Source
breakAll :: (a -> Bool) -> [a] -> [[a]]Source
Break list into a list of sublists, separated by element satisfying supplied condition.
powerSet :: [a] -> [[a]]Source
Powerset of a list, in ascending order of size. Assumes the supplied list has no duplicate elements.
permutations :: [a] -> [[a]]Source
listProduct :: [[a]] -> [[a]]Source
Given a list of lists, construct a new list of lists where each member of the new list is the same length as the original list, and each member corresponds to a different choice of one element from each of the original members in the corresponding position. Thus:
listProduct [[a1,a2],[b1],[c1,c2]] = [ [a1,b1,c1], [a1,b1,c2], [a2,b1,c1], [a2,b1,c2] ]
Note: The length of the resulting list is the prodicty of lengths of the components of the original list. Thus, if any member of the original list is empty then so is the resulting list:
listProduct [[a1,a2],[],[c1,c2]] = []
NOTE: this is subsumed by sequence
powerSequencesLen :: Int -> [a] -> [[a]]Source
Return all powersequences of a given length