Module "List.curry"

Library with some useful operations on lists.

Author: Michael Hanus

Version: March 2009

Functions:
delete | deleteBy | elemIndex | elemIndices | find | findIndex | findIndices | group | groupBy | insertBy | intersect | intersperse | isPrefixOf | isSuffixOf | last | nub | nubBy | partition | replace | sortBy | transpose | union | \\

elemIndex  :: 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  :: 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  :: [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  :: 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.

(\\)  :: [a] -> [a] -> [a]              Computes the difference of two lists.

union  :: [a] -> [a] -> [a]              Computes the union of two lists.

intersect  :: [a] -> [a] -> [a]              Computes the intersection of two lists.

intersperse  :: a -> [a] -> [a]              Puts a separator element between all elements in a list.

transpose  :: [[a]] -> [[a]]              Transposes the rows and columns 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  :: [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.

replace  :: a -> Int -> [a] -> [a]              Replaces an element in a list.

isPrefixOf  :: [a] -> [a] -> Bool              Checks whether a list is a prefix of another.

isSuffixOf  :: [a] -> [a] -> Bool              Checks whether a list is a suffix of 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.

Returns the index i of the first occurrence of an element in a list as (Just i), otherwise Nothing is returned.

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elemIndices :: a -> [a] -> [Int]   

Returns the list of indices of occurrences of an element in a list.

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find :: (a -> Bool) -> [a] -> Maybe a   

Returns the first element e of a list satisfying a predicate as (Just e), otherwise Nothing is returned.

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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.

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findIndices :: (a -> Bool) -> [a] -> [Int]   

Returns the list of indices of list elements satisfying a predicate.

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nub :: [a] -> [a]   

Removes all duplicates in the argument list.

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nubBy :: (a -> a -> Bool) -> [a] -> [a]   

Removes all duplicates in the argument list according to an equivalence relation.

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delete :: a -> [a] -> [a]   

Deletes the first occurrence of an element in a list.

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deleteBy :: (a -> a -> Bool) -> a -> [a] -> [a]   

Deletes the first occurrence of an element in a list according to an equivalence relation.

Further infos:

• incompletely defined

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(\\) :: [a] -> [a] -> [a]   

Computes the difference of two lists.

Example call:  (xs \\ ys)

Parameters:

xs - a list

ys - a list

Returns:

the list where the first occurrence of each element of ys has been removed from xs

Further infos:

• defined as non-associative infix operator with precedence 5

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union :: [a] -> [a] -> [a]   

Computes the union of two lists.

Further infos:

• incompletely defined

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intersect :: [a] -> [a] -> [a]   

Computes the intersection of two lists.

Further infos:

• incompletely defined

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intersperse :: a -> [a] -> [a]   

Puts a separator element between all elements in a list.
Example: (intersperse 9 [1,2,3,4]) = [1,9,2,9,3,9,4]

Further infos:

• solution complete, i.e., able to compute all solutions

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transpose :: [[a]] -> [[a]]   

Transposes the rows and columns of the argument.
Example: (transpose [[1,2,3],[4,5,6]]) = [[1,4],[2,5],[3,6]]

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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.
Example: (partition (<4) [8,1,5,2,4,3]) = ([1,2,3],[8,5,4])

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group :: [a] -> [[a]]   

Splits the list argument into a list of lists of equal adjacent elements.
Example: (group [1,2,2,3,3,3,4]) = [[1],[2,2],[3,3,3],[4]]

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groupBy :: (a -> a -> Bool) -> [a] -> [[a]]   

Splits the list argument into a list of lists of related adjacent elements.

Example call:  (groupBy eq xs)

Parameters:

eq - the relation to classify adjacent elements

xs - the list of elements

Returns:

the list of lists of related adjacent elements

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replace :: a -> Int -> [a] -> [a]   

Replaces an element in a list.

Example call:  (replace x p ys)

Parameters:

x - the new element

p - the position of the new element (head = 0)

ys - the old list

Returns:

the new list where the p. element is replaced by x

Further infos:

• incompletely defined

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isPrefixOf :: [a] -> [a] -> Bool   

Checks whether a list is a prefix of another.

Example call:  (isPrefixOf xs ys)

Parameters:

xs - a list

ys - a list

Returns:

True if xs is a prefix of ys

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isSuffixOf :: [a] -> [a] -> Bool   

Checks whether a list is a suffix of another.

Example call:  (isSuffixOf xs ys)

Parameters:

xs - a list

ys - a list

Returns:

True if xs is a suffix of ys

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sortBy :: (a -> a -> Bool) -> [a] -> [a]   

Sorts a list w.r.t. an ordering relation by the insertion method.

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insertBy :: (a -> a -> Bool) -> a -> [a] -> [a]   

Inserts an object into a list according to an ordering relation.

Example call:  (insertBy le x xs)

Parameters:

le - an ordering relation (e.g., less-or-equal)

x - an element

xs - a list

Returns:

a list where the element has been inserted

Further infos:

• incompletely defined

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last :: [a] -> a   

Returns the last element of a non-empty list.

Further infos:

• incompletely defined
• solution complete, i.e., able to compute all solutions

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