Library with some useful operations on lists.
Author: Michael Hanus, Bjoern Peemoeller
Version: Februar 2016
elemIndex
:: Eq a => a -> [a] -> Maybe Int
Returns the index i
of the first occurrence of an element in a list
as (Just i) , otherwise Nothing
is returned.
|
elemIndices
:: Eq a => a -> [a] -> [Int]
Returns the list of indices of occurrences of an element in a list. |
find
:: (a -> Bool) -> [a] -> Maybe a
Returns the first element e
of a list satisfying a predicate
as (Just e) ,
otherwise Nothing
is returned.
|
findIndex
:: (a -> Bool) -> [a] -> Maybe Int
Returns the index i
of the first occurrences of a list element
satisfying a predicate as (Just i) , otherwise Nothing
is returned.
|
findIndices
:: (a -> Bool) -> [a] -> [Int]
Returns the list of indices of list elements satisfying a predicate. |
nub
:: Eq a => [a] -> [a]
Removes all duplicates in the argument list. |
nubBy
:: (a -> a -> Bool) -> [a] -> [a]
Removes all duplicates in the argument list according to an equivalence relation. |
delete
:: Eq a => a -> [a] -> [a]
Deletes the first occurrence of an element in a list. |
deleteBy
:: (a -> a -> Bool) -> a -> [a] -> [a]
Deletes the first occurrence of an element in a list according to an equivalence relation. |
(\\)
:: Eq a => [a] -> [a] -> [a]
Computes the difference of two lists. |
union
:: Eq a => [a] -> [a] -> [a]
Computes the union of two lists. |
unionBy
:: (a -> a -> Bool) -> [a] -> [a] -> [a]
Computes the union of two lists according to the given equivalence relation |
intersect
:: Eq a => [a] -> [a] -> [a]
Computes the intersection of two lists. |
intersectBy
:: (a -> a -> Bool) -> [a] -> [a] -> [a]
Computes the intersection of two lists according to the given equivalence relation |
intersperse
:: a -> [a] -> [a]
Puts a separator element between all elements in a list. |
intercalate
:: [a] -> [[a]] -> [a]
intercalate xs xss
is equivalent to (concat (intersperse xs xss)) .
|
transpose
:: [[a]] -> [[a]]
Transposes the rows and columns of the argument. |
diagonal
:: [[a]] -> [a]
Diagonalization of a list of lists. |
permutations
:: [a] -> [[a]]
Returns the list of all permutations of the argument. |
partition
:: (a -> Bool) -> [a] -> ([a],[a])
Partitions a list into a pair of lists where the first list contains those elements that satisfy the predicate argument and the second list contains the remaining arguments. |
group
:: Eq a => [a] -> [[a]]
Splits the list argument into a list of lists of equal adjacent elements. |
groupBy
:: (a -> a -> Bool) -> [a] -> [[a]]
Splits the list argument into a list of lists of related adjacent elements. |
splitOn
:: Eq a => [a] -> [a] -> [[a]]
Breaks the second list argument into pieces separated by the first list argument, consuming the delimiter. |
split
:: (a -> Bool) -> [a] -> [[a]]
Splits a list into components delimited by separators, where the predicate returns True for a separator element. |
inits
:: [a] -> [[a]]
Returns all initial segments of a list, starting with the shortest. |
tails
:: [a] -> [[a]]
Returns all final segments of a list, starting with the longest. |
replace
:: a -> Int -> [a] -> [a]
Replaces an element in a list. |
isPrefixOf
:: Eq a => [a] -> [a] -> Bool
Checks whether a list is a prefix of another. |
isSuffixOf
:: Eq a => [a] -> [a] -> Bool
Checks whether a list is a suffix of another. |
isInfixOf
:: Eq a => [a] -> [a] -> Bool
Checks whether a list is contained in another. |
sortBy
:: (a -> a -> Bool) -> [a] -> [a]
Sorts a list w.r.t. |
insertBy
:: (a -> a -> Bool) -> a -> [a] -> [a]
Inserts an object into a list according to an ordering relation. |
last
:: [a] -> a
Returns the last element of a non-empty list. |
init
:: [a] -> [a]
Returns the input list with the last element removed. |
sum
:: Num a => [a] -> a
Returns the sum of a list of integers. |
product
:: Num a => [a] -> a
Returns the product of a list of integers. |
maximum
:: Ord a => [a] -> a
Returns the maximum of a non-empty list. |
maximumBy
:: (a -> a -> Ordering) -> [a] -> a
Returns the maximum of a non-empty list according to the given comparison function |
minimum
:: Ord a => [a] -> a
Returns the minimum of a non-empty list. |
minimumBy
:: (a -> a -> Ordering) -> [a] -> a
Returns the minimum of a non-empty list according to the given comparison function |
scanl
:: (a -> b -> a) -> a -> [b] -> [a]
scanl
is similar to foldl , but returns a list of successive
reduced values from the left:
scanl f z [x1, x2, ...] == [z, z f
x1, (z f
x1) f
x2, ...]
|
scanl1
:: (a -> a -> a) -> [a] -> [a]
scanl1
is a variant of scanl
that has no starting value argument:
scanl1 f [x1, x2, ...] == [x1, x1 f
x2, ...]
|
scanr
:: (a -> b -> b) -> b -> [a] -> [b]
scanr
is the right-to-left dual of scanl .
|
scanr1
:: (a -> a -> a) -> [a] -> [a]
scanr1
is a variant of scanr
that has no starting value argument.
|
mapAccumL
:: (a -> b -> (a,c)) -> a -> [b] -> (a,[c])
The mapAccumL
function behaves like a combination of map
and
foldl ; it applies a function to each element of a list, passing
an accumulating parameter from left to right, and returning a final
value of this accumulator together with the new list.
|
mapAccumR
:: (a -> b -> (a,c)) -> a -> [b] -> (a,[c])
The mapAccumR
function behaves like a combination of map
and
foldr ; it applies a function to each element of a list, passing
an accumulating parameter from right to left, and returning a final
value of this accumulator together with the new list.
|
cycle
:: [a] -> [a]
Builds an infinite list from a finite one. |
unfoldr
:: (a -> Maybe (b,a)) -> a -> [b]
Builds a list from a seed value. |
Returns the index |
Returns the list of indices of occurrences of an element in a list. |
Returns the first element |
Returns the index |
Returns the list of indices of list elements satisfying a predicate. |
Removes all duplicates in the argument list. |
Removes all duplicates in the argument list according to an equivalence relation. |
Deletes the first occurrence of an element in a list. |
Deletes the first occurrence of an element in a list according to an equivalence relation. |
Computes the difference of two lists.
|
Computes the union of two lists. |
Computes the union of two lists according to the given equivalence relation |
Computes the intersection of two lists. |
Computes the intersection of two lists according to the given equivalence relation |
Puts a separator element between all elements in a list.
Example:
|
|
Transposes the rows and columns of the argument.
Example: |
Diagonalization of a list of lists. Fairly merges (possibly infinite) list of (possibly infinite) lists.
|
Returns the list of all permutations of the argument. |
Partitions a list into a pair of lists where the first list contains those elements that satisfy the predicate argument and the second list contains the remaining arguments.
Example: |
Splits the list argument into a list of lists of equal adjacent elements.
Example: |
Splits the list argument into a list of lists of related adjacent elements.
|
Breaks the second list argument into pieces separated by the first list argument, consuming the delimiter. An empty delimiter is invalid, and will cause an error to be raised. |
Splits a list into components delimited by separators, where the predicate returns True for a separator element. The resulting components do not contain the separators. Two adjacent separators result in an empty component in the output.
|
Returns all initial segments of a list, starting with the shortest.
Example:
|
Returns all final segments of a list, starting with the longest.
Example:
|
Replaces an element in a list.
|
Checks whether a list is a prefix of another.
|
Checks whether a list is a suffix of another.
|
Checks whether a list is contained in another.
|
Sorts a list w.r.t. an ordering relation by the insertion method. |
Inserts an object into a list according to an ordering relation.
|
Returns the last element of a non-empty list.
|
Returns the input list with the last element removed.
|
Returns the sum of a list of integers. |
Returns the product of a list of integers. |
Returns the maximum of a non-empty list.
|
Returns the maximum of a non-empty list according to the given comparison function
|
Returns the minimum of a non-empty list.
|
Returns the minimum of a non-empty list according to the given comparison function
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The |
The |
Builds an infinite list from a finite one.
|
Builds a list from a seed value. |