List
case Nil
case Cons(t, List[t])
The List type.
A list is either the empty list represented by Nil
, or
an element v
followed by a list vs
represented by v :: vs
.
Instances
instance Applicative[List]
Sourceinstance Collectable[List[a]]
Sourceinstance Filterable[List]
Sourceinstance Traversable[List]
Sourceinstance UnorderedFoldable[List]
Sourceinstance Witherable[List]
SourceDefinitions
def ap(f: List[a -> b \ ef], x: List[a]): List[b] \ ef
SourceApply every function from f
to every argument from x
and return a list with all results.
For f = f1, f2, ...
and x = x1, x2, ...
the results appear in the order
f1(x1), f1(x2), ..., f2(x1), f2(x2), ...
.
def append(l1: List[a], l2: List[a]): List[a]
SourceReturns l2
appended to l1
.
The infix operator :::
is an alias for append
(l1 ::: l2 = append(l1, l2)
).
def count(f: a -> Bool \ ef, l: List[a]): Int32 \ ef
SourceReturns the number of elements in l
that satisfy the predicate f
.
Returns the list l
with duplicates removed. The first occurence of
an element is kept and except for the removal of subsequent duplicates
the order of l
is preserved.
distinct
uses the Flix's builtin equality test. Use distinctWith
if you
need a custom equality test.
def distinctWith(f: a -> (a -> Bool), l: List[a]): List[a]
SourceReturns the list l
with duplicates removed using the supplied function
f
for comparison. The first occurrence of an element is kept and except
for the removal of subsequent duplicates the order of l
is preserved.
def drop(n: Int32, l: List[a]): List[a]
SourceReturns l
without the first n
elements.
Returns Nil
if n > length(l)
.
Returns l
if n < 0
.
def dropWhile(f: a -> Bool \ ef, l: List[a]): List[a] \ ef
SourceReturns l
without the longest prefix that satisfies the predicate f
.
def empty(): List[a]
SourceReturns the empty list Nil
.
def enumerator(rc: Region[r], l: List[a]): Iterator[(Int32, a), r, r] \ r
SourceReturns an iterator over l
zipped with the indices of the elements.
def exists(f: a -> Bool \ ef, l: List[a]): Bool \ ef
SourceReturns true
if and only if at least one element in l
satisfies the predicate f
.
Returns false
if l
is empty.
def filter(f: a -> Bool \ ef, l: List[a]): List[a] \ ef
SourceReturns a list of every element in l
that satisfies the predicate f
.
def filterMap(f: a -> Option[b] \ ef, l: List[a]): List[b] \ ef
SourceCollects the results of applying the partial function f
to every element in l
.
def find(f: a -> Bool \ ef, l: List[a]): Option[a] \ ef
SourceAlias for findLeft
.
def findLeft(f: a -> Bool \ ef, l: List[a]): Option[a] \ ef
SourceOptionally returns the first element of l
that satisfies the predicate f
when searching from left to right.
def findMap(f: a -> Option[b] \ ef, l: List[a]): Option[b] \ ef
SourceReturns the first non-None result of applying the partial function f
to each element of l
.
Returns None
if every element of l
is None
.
def findRight(f: a -> Bool \ ef, l: List[a]): Option[a] \ ef
SourceOptionally returns the first element of l
that satisfies the predicate f
when searching from right to left.
def flatMap(f: a -> List[b] \ ef, l: List[a]): List[b] \ ef
SourceReturns the result of applying f
to every element in l
and concatenating the results.
def flatten(l: List[List[a]]): List[a]
SourceReturns the concatenation of the elements in l
.
Returns the result of applying combine
to all the elements in l
, using empty
as the initial value.
def fold2(f: c -> (a -> (b -> c \ ef)), c: c, l1: List[a], l2: List[b]): c \ ef
SourceAlias for foldLeft2
.
def foldLeft(f: b -> (a -> b \ ef), s: b, l: List[a]): b \ ef
SourceApplies f
to a start value s
and all elements in l
going from left to right.
That is, the result is of the form: f(...f(f(s, x1), x2)..., xn)
.
def foldLeft2(f: c -> (a -> (b -> c \ ef)), c: c, l1: List[a], l2: List[b]): c \ ef
SourceAccumulates the result of applying f
pairwise to the elements of l1
and l2
starting with the initial value c
and going from left to right.
Returns the result of mapping each element and combining the results.
def foldRight(f: a -> (b -> b \ ef), s: b, l: List[a]): b \ ef
SourceApplies f
to a start value s
and all elements in l
going from right to left.
That is, the result is of the form: f(x1, ...f(xn-1, f(xn, s))...)
.
def foldRight2(f: a -> (b -> (c -> c \ ef)), c: c, l1: List[a], l2: List[b]): c \ ef
SourceAccumulates the result of applying f
pairwise to the elements of l1
and l2
starting with the initial value c
and going from right to left.
def foldRightWithCont(f: a -> ((Unit -> b \ ef) -> b \ ef), z: b, l: List[a]): b \ ef
SourceApplies f
to a start value z
and all elements in l
going from right to left.
That is, the result is of the form: f(x1, ...f(xn-1, f(xn, z))...)
.
A foldRightWithCont
allows early termination by not calling the continuation.
def forAll(f: a -> Bool \ ef, l: List[a]): Bool \ ef
SourceReturns true
if and only if all elements in l
satisfy the predicate f
.
Returns true
if l
is empty.
def forEach(f: a -> Unit \ ef, l: List[a]): Unit \ ef
SourceApplies f
to every element of l
.
def forEachWithIndex(f: Int32 -> (a -> Unit \ ef), l: List[a]): Unit \ ef
SourceApplies f
to every element of l
along with that element's index.
Returns the frequency for each element in list l
def groupBy(f: a -> (a -> Bool), l: List[a]): List[List[a]]
SourcePartitions l
into sublists such that for any two elements x
and y
in a sublist, f(x, y)
is true.
A sublist is created by iterating through the remaining elements of l
from left to right and adding an
element to the sublist if and only if doing so creates no conflicts with the elements already in the sublist.
The function f
must be pure.
def head(l: List[a]): Option[a]
SourceReturns Some(x)
if x
is the first element of l
.
Returns None
if l
is empty.
Optionally returns the position of x
in l
.
def init(l: List[a]): Option[List[a]]
SourceReturns the sublist of l
without the last element.
Returns None
if the list l
is Nil
.
def intercalate(l1: List[a], l2: List[List[a]]): List[a]
SourceReturns the concatenation of the elements in l2
with the elements of l1
inserted between every two adjacent elements.
That is, returns y1 :: x1 ... xn :: y2 :: ... yn-1 :: x1 :: ... :: xn :: yn :: Nil
.
def intersperse(a: a, l: List[a]): List[a]
SourceReturns l
with x
inserted between every two adjacent elements.
def isEmpty(l: List[a]): Bool
SourceReturns true if and only if l
is the empty list, i.e. Nil
.
Returns true
if and only if l1
is an infix of l2
.
Returns true
if and only if l1
is a prefix of l2
.
Returns true
if and only if l1
is a suffix of l2
.
def iterator(rc: Region[r], xs: List[a]): Iterator[a, r, r] \ r
SourceReturns an iterator over l
.
Returns the concatenation of the string representation
of each element in l
with sep
inserted between each element.
def joinWith(f: a -> String \ ef, sep: String, l: List[a]): String \ ef
SourceReturns the concatenation of the string representation
of each element in l
according to f
with sep
inserted between each element.
def last(l: List[a]): Option[a]
SourceReturns Some(x)
if x
is the last element of l
.
Returns None
if l
is empty.
def length(l: List[a]): Int32
SourceReturns the number of elements in l
.
def map(f: a -> b \ ef, l: List[a]): List[b] \ ef
SourceReturns the result of applying f
to every element in l
.
That is, the result is of the form: f(x1) :: f(x2) :: ...
.
def map2(f: t1 -> (t2 -> r \ ef), l1: List[t1], l2: List[t2]): List[r] \ ef
SourceLift a binary function to work on lists of its original arguments, returning a list
of applying all combinations of arguments.
For argument lists l1 = x1, x2, ...
and l2 = y1, y2, ...
the results appear in the order
f(x1,y1), f(x1,y2), ..., f(x2,y1), f(x2,y2), ...
.
def map3(f: t1 -> (t2 -> (t3 -> r \ ef)), l1: List[t1], l2: List[t2], l3: List[t3]): List[r] \ ef
SourceLift a ternary function to work on lists of its original arguments, returning a list
of applying all combinations of arguments.
For argument lists l1 = x1, x2, ...
, l2 = y1, y2, ...
and l3 = z1, z2, ...
the results appear
in the following order:
`
f(x1,y1,z1), f(x1,y1,z2), ..., f(x1,y2,z1), f(x1,y2,z2), ...,
f(x2,y1,z1), f(x2,y1,z2), ..., f(x2,y2,z1), f(x2,y2,z2), ...`
...
`
def map4(f: t1 -> (t2 -> (t3 -> (t4 -> r \ ef))), l1: List[t1], l2: List[t2], l3: List[t3], l4: List[t4]): List[r] \ ef
SourceLift a 4-ary function to work on lists of its original arguments, returning a list
of applying all combinations of arguments. The results appear in the order extending the pattern from map3
.
def map5(f: t1 -> (t2 -> (t3 -> (t4 -> (t5 -> r \ ef)))), l1: List[t1], l2: List[t2], l3: List[t3], l4: List[t4], l5: List[t5]): List[r] \ ef
SourceLift a 5-ary function to work on lists of its original arguments, returning a list
of applying all combinations of arguments. The results appear in the order extending the pattern from map3
.
def mapWithIndex(f: Int32 -> (a -> b \ ef), l: List[a]): List[b] \ ef
SourceReturns the result of applying f
to every element in l
along with that element's index.
That is, the result is of the form: f(x1, 0) :: f(x2, 1) :: ...
.
Optionally finds the largest element of l
according to the Order
on a
.
Returns None
if l
is empty.
def maximumBy(cmp: a -> (a -> Comparison), l: List[a]): Option[a]
SourceOptionally finds the largest element of l
according to the given comparator cmp
.
Returns None
if l
is empty.
Returns true
if and only if l
contains the element x
.
Merges the two lists l1
and l2
. Assuming they are both sorted.
If two elements compare EqualTo
, then the element of l1
is first in the result.
Optionally finds the smallest element of l
according to the Order
on a
.
Returns None
if l
is empty.
def minimumBy(cmp: a -> (a -> Comparison), l: List[a]): Option[a]
SourceOptionally finds the smallest element of l
according to the given comparator cmp
.
Returns None
if l
is empty.
def nonEmpty(l: List[a]): Bool
SourceReturns true if and only if l
is a non-empty list.
def partition(f: a -> Bool \ ef, l: List[a]): (List[a], List[a]) \ ef
SourceReturns a pair of lists (l1, l2)
.
l1
contains all elements of l
that satisfy the predicate f
.
l2
contains all elements of l
that do not satisfy the predicate f
.
def patch(i: Int32, n: Int32, l1: List[a], l2: List[a]): List[a]
SourceReturns l2
with the n
elements starting at index i
replaced with the elements of l1
.
If any of the indices i, i+1, i+2, ... , i+n-1
are out of range in l2
then no patching is done at these indices.
If l1
becomes depleted then no further patching is done.
If patching occurs at index i+j
in l2
, then the element at index j
in l1
is used.
def permutations(l: List[a]): List[List[a]]
SourceReturns all permutations of l
in lexicographical order by element indices in l
.
That is, l
is the first permutation and reverse(l)
is the last permutation.
def point(a: a): List[a]
SourceReturn the singleton list with element x
.
def range(b: Int32, e: Int32): List[Int32]
SourceReturns a list of all integers between b
(inclusive) and e
(exclusive).
Returns Nil
if b >= e
.
def reduceLeft(f: a -> (a -> a \ ef), l: List[a]): Option[a] \ ef
SourceApplies f
to all elements in l
going from left to right until a single value v
is obtained. Returns Some(v)
.
That is, the result is of the form: Some(f(...f(f(x1, x2), x3)..., xn))
Returns None
if l
is empty.
def reduceRight(f: a -> (a -> a \ ef), l: List[a]): Option[a] \ ef
SourceApplies f
to all elements in l
going from right to left until a single value v
is obtained. Returns Some(v)
.
That is, the result is of the form: Some(f(x1, ...f(xn-2, f(xn-1, xn))...))
Returns None
if l
is empty.
def repeat(n: Int32, a: a): List[a]
SourceReturns a list with the element x
repeated n
times.
Returns Nil
if n < 0
.
Returns l
with every occurrence of src
replaced by dst
.
def reverse(l: List[a]): List[a]
SourceReturns the reverse of l
.
def rotateLeft(n: Int32, l: List[a]): List[a]
SourceReturns l
with its elements rotated n
positions to the left.
That is, returns a new list where the first n mod length(l)
elements in l
are the last n mod length(l)
elements of the new list.
def rotateRight(n: Int32, l: List[a]): List[a]
SourceReturns l
with its elements rotated n
positions to the right.
That is, returns a new list where the last n mod length(l)
elements in l
are the first n mod length(l)
elements of the new list.
def scan(f: b -> (a -> b \ ef), s: b, l: List[a]): List[b] \ ef
SourceAlias for scanLeft
.
def scanLeft(f: b -> (a -> b \ ef), s: b, l: List[a]): List[b] \ ef
SourceAccumulates the result of applying f
to l
going left to right.
That is, the result is of the form: s :: f(s, x1) :: f(f(s, x1), x2) ...
.
def scanRight(f: a -> (b -> b \ ef), s: b, l: List[a]): List[b] \ ef
SourceAccumulates the result of applying f
to l
going right to left.
That is, the result is of the form: ... f(xn-1, f(xn, s)) :: f(xn, s) :: s
.
def sequence(l: List[m[a]]): m[List[a]] with Applicative[m]
SourceReturns the result of running all the actions in the list l
going from left
to right.
def shuffle(l: List[a]): List[a] \ NonDet
SourceShuffles l
using the Fisher–Yates shuffle.
def size(l: List[a]): Int32
SourceReturns the number of elements in l
.
def slice(start: { start = Int32 }, end: { end = Int32 }, l: List[a]): List[a]
SourceReturns the sublist of l
from index start
(inclusive) to index end
(exclusive).
That is, an element at index i
in l
is part of the returned sublist if and only if i >= start
and i < end
.
Note: Indices that are out of bounds in l
are not considered (i.e. slice(start, end, l) = slice(max(0, start), min(length(l), end), l)).
Sort list l
so that elements are ordered from low to high according to their Order
instance.
The sort is not stable, i.e., equal elements may appear in a different order than in the input l
.
The sort implementation is a Quicksort.
Sort list l
so that elements are ordered from low to high according to the Order
instance
for the values obtained by applying f
to each element.
The sort is not stable, i.e., equal elements may appear in a different order than in the input l
.
The sort implementation is a Quicksort.
def sortWith(cmp: a -> (a -> Comparison), l: List[a]): List[a]
SourceSort list l
so that elements are ordered from low to high according to the comparison function cmp
.
The sort is not stable, i.e., equal elements may appear in a different order than in the input l
.
The sort implementation is a Quicksort.
def span(f: a -> Bool, l: List[a]): (List[a], List[a])
SourceReturns a pair of lists (l1, l2)
.
l1
is the longest prefix of l
that satisfies the predicate f
.
l2
is the remainder of l
.
The function f
must be pure.
def splitAt(n: Int32, xs: List[a]): (List[a], List[a])
SourceSplit the list xs
at the position n
returning the left and right parts.
Position n
is included in the right part.
Example: splitAt(2, 1::2::3::4::Nil)
returns (1::2::Nil, 3::4::Nil)
Returns (xs, Nil)
if n > length(xs)
.
Returns (Nil, xs)
if n < 0
.
def subsequences(l: List[a]): List[List[a]]
SourceReturns all subsequences of l
in lexicographical order by element indices in l
.
That is, l
is the first subsequence and Nil
is the last subsequence.
def sum(l: List[Int32]): Int32
SourceReturns the sum of all elements in the list l
.
def sumWith(f: a -> Int32 \ ef, l: List[a]): Int32 \ ef
SourceReturns the sum of all elements in the list l
according to the function f
.
def take(n: Int32, l: List[a]): List[a]
SourceReturns the first n
elements of l
.
Returns l
if n > length(l)
.
Returns Nil
if n < 0
.
def takeWhile(f: a -> Bool \ ef, l: List[a]): List[a] \ ef
SourceReturns the longest prefix of l
that satisfies the predicate f
.
def toArray(rc: Region[r], l: List[a]): Array[a, r] \ r
SourceReturns the list l
as an array.
def toChain(l: List[a]): Chain[a]
SourceReturns the list l
as a chain.
Returns the association list l
as a DelayMap
.
If l
contains multiple mappings with the same key, toDelayMap
does not
make any guarantees about which mapping will be in the resulting map.
Returns the association list l
as a map.
If l
contains multiple mappings with the same key, toMap
does not
make any guarantees about which mapping will be in the resulting map.
Returns a map with elements of s
as keys and f
applied as values.
If s
contains multiple mappings with the same key, toMapWith
does not
make any guarantees about which mapping will be in the resulting map.
def toMutDeque(rc: Region[r], l: List[a]): MutDeque[a, r] \ r
SourceReturns l
as a MutDeque.
def toMutList(rc: Region[r], l: List[a]): MutList[a, r] \ r
SourceReturns l
as a mutable list.
def toNec(l: List[a]): Option[Nec[a]]
SourceReturns the list l
as Option[Nec[a]]
.
If l
is empty return None
, otherwise return the Nec wrapped in Some
.
def toNel(l: List[a]): Option[Nel[a]]
SourceReturns the list l
as Option[Nel[a]]
.
If l
is empty return None
, otherwise return the Nel wrapped in Some
.
def toVector(l: List[a]): Vector[a]
SourceReturns the list l
as a vector.
def transpose(l: List[List[a]]): List[List[a]]
SourceReturns the transpose of l
.
Returns l
if the dimensions of the elements of l
are mismatched.
def traverse(f: a -> m[b] \ ef, l: List[a]): m[List[b]] \ ef with Applicative[m]
SourceReturns the result of applying the applicative mapping function f
to all the elements of the
list l
going from left to right.
def unfold(f: s -> Option[(a, s)] \ ef, st: s): List[a] \ ef
SourceBuild a list by applying f
to the seed value st
.
f
should return Some(a,st1)
to signal a new list element a
and a new seed value st1
.
f
should return None
to signal the end of building the list.
def unfoldWithIter(next: Unit -> Option[a] \ ef): List[a] \ ef
SourceBuild a list by applying the function next
to ()
. next
is expected to encapsulate
a stateful resource such as a file handle that can be iterated.
next
should return Some(a)
to signal a new list element a
.
next
should return None
to signal the end of building the list.
def unfoldWithOkIter(next: Unit -> Result[e, Option[a]] \ ef): Result[e, List[a]] \ ef
SourceBuild a list by applying the function next
to ()
. next
is expected to encapsulate
a stateful resource such as a file handle that can be iterated.
next
should return Ok(Some(a)
to signal a new list element Ok(a)
.
next
should return Ok(None)
to signal the end of building the list.
next
should return Err(e)
to signal that an error occurred. The function returns Err(e)
.
def unzip(l: List[(a, b)]): (List[a], List[b])
SourceReturns a pair of lists, the first containing all first components in l
and the second containing all second components in l
.
def unzip3(l: List[(a, b, c)]): (List[a], List[b], List[c])
SourceReturns a triple of lists, the first containing all first components in l
the second containing all second components in l
and the third containing all
third components in l
.
def update(i: Int32, a: a, l: List[a]): List[a]
SourceReturns l
with the element at index i
replaced by x
.
Returns l
if i < 0
or i > length(l)-1
.
def zip(l1: List[a], l2: List[b]): List[(a, b)]
SourceReturns a list where the element at index i
is (a, b)
where
a
is the element at index i
in l1
and b
is the element at index i
in l2
.
If either l1
or l2
becomes depleted, then no further elements are added to the resulting list.
def zip3(l1: List[a], l2: List[b], l3: List[c]): List[(a, b, c)]
SourceReturns a list where the element at index i
is (a, b, c)
where
a
is the element at index i
in l1
, b
is the element at index i
in l2
and c
is the element at index i
in l3
.
If any one of l1
, l2
or l3
become depleted, then no further elements are added to the resulting list.
def zipWith(f: a -> (b -> c \ ef), l1: List[a], l2: List[b]): List[c] \ ef
SourceReturns a list where the element at index i
is f(a, b)
where
a
is the element at index i
in l1
and b
is the element at index i
in l2
.
If either l1
or l2
becomes depleted, then no further elements are added to the resulting list.
def zipWith3(f: a -> (b -> (c -> d \ ef)), l1: List[a], l2: List[b], l3: List[c]): List[d] \ ef
SourceReturns a list where the element at index i
is f(a, b, c)
where
a
is the element at index i
in l1
, b
is the element at index i
in l2
and c
is the element at index i
in l3
.
If any one of l1
, l2
or l3
become depleted, then no further elements are added to the resulting list.
def zipWithA(f: a -> (b -> f[c] \ ef), xs: List[a], ys: List[b]): f[List[c]] \ ef with Applicative[f]
SourceGeneralize zipWith
to an applicative functor f
.
def zipWithIndex(l: List[a]): List[(Int32, a)]
SourceReturns a list where each element e
is mapped to (i, e)
where i
is the index of e
.