T
- Component type of the Listpublic interface List<T> extends Kind1<List<?>,T>, LinearSeq<T>, Stack<T>
List
is an eager sequence of elements. Its immutability makes it suitable for concurrent programming.
A List
is composed of a head
element and a tail
List
.
There are two implementations of the List
interface:
List.Nil
, which represents the empty List
.List.Cons
, which represents a List
containing one or more elements.List
:
// factory methods
List.empty() // = List.of() = Nil.instance()
List.of(x) // = new Cons<>(x, Nil.instance())
List.of(Object...) // e.g. List.of(1, 2, 3)
List.ofAll(Iterable) // e.g. List.ofAll(Stream.of(1, 2, 3)) = 1, 2, 3
List.ofAll(<primitive array>) // e.g. List.of(new int[] {1, 2, 3}) = 1, 2, 3
// int sequences
List.range(0, 3) // = 0, 1, 2
List.rangeClosed(0, 3) // = 0, 1, 2, 3
Note: A List
is primary a Seq
and extends Stack
for technical reasons (so Stack
does not need to wrap List
).
If operating on a List
, please prefer
prepend(Object)
over push(Object)
prependAll(Iterable)
over pushAll(Iterable)
tail()
over pop()
tailOption()
over popOption()
List<Integer> s1 = List.of(1);
List<Integer> s2 = List.of(1, 2, 3);
// = List.of(new Integer[] {1, 2, 3});
List<int[]> s3 = List.ofAll(new int[] {1, 2, 3});
List<List<Integer>> s4 = List.ofAll(List.of(1, 2, 3));
List<Integer> s5 = List.ofAll(new int[] {1, 2, 3});
List<Integer> s6 = List.ofAll(List.of(1, 2, 3));
// cuckoo's egg
List<Integer[]> s7 = List.<Integer[]> of(new Integer[] {1, 2, 3});
Example: Converting a String to digits
// = List(1, 2, 3)
List.of("123".toCharArray()).map(c -> Character.digit(c, 10))
See Okasaki, Chris: Purely Functional Data Structures (p. 7 ff.). Cambridge, 2003.Modifier and Type | Interface and Description |
---|---|
static class |
List.Cons<T>
Non-empty
List , consisting of a head and a tail . |
static class |
List.Nil<T>
Representation of the singleton empty
List . |
λ.Memoized
Modifier and Type | Field and Description |
---|---|
static long |
serialVersionUID |
Modifier and Type | Method and Description |
---|---|
default List<T> |
append(T element)
Appends an element to this.
|
default List<T> |
appendAll(Iterable<? extends T> elements)
Appends all given elements to this.
|
static <T> Collector<T,ArrayList<T>,List<T>> |
collector()
Returns a
Collector which may be used in conjunction with
Stream.collect(java.util.stream.Collector) to obtain a List . |
default List<List<T>> |
combinations()
Returns the union of all combinations from k = 0 to length().
|
default List<List<T>> |
combinations(int k)
Returns the k-combination of this traversable, i.e.
|
default Iterator<List<T>> |
crossProduct(int power)
Calculates the n-ary cartesian power (or cross product or simply product) of this.
|
default List<T> |
distinct()
Returns a new version of this which contains no duplicates.
|
default List<T> |
distinctBy(Comparator<? super T> comparator)
Returns a new version of this which contains no duplicates.
|
default <U> List<T> |
distinctBy(Function<? super T,? extends U> keyExtractor)
Returns a new version of this which contains no duplicates.
|
default List<T> |
drop(long n)
Drops the first n elements of this or all elements, if this length < n.
|
default List<T> |
dropRight(long n)
Drops the last n elements of this or all elements, if this length < n.
|
default List<T> |
dropUntil(Predicate<? super T> predicate)
Drops elements until the predicate holds for the current element.
|
default List<T> |
dropWhile(Predicate<? super T> predicate)
Drops elements while the predicate holds for the current element.
|
static <T> List<T> |
empty()
Returns the single instance of Nil.
|
static <T> List<T> |
fill(int n,
Supplier<? extends T> s)
Returns a List containing
n values supplied by a given Supplier s . |
default List<T> |
filter(Predicate<? super T> predicate)
Returns a new traversable consisting of all elements which satisfy the given predicate.
|
default <U> List<U> |
flatMap(Function<? super T,? extends Iterable<? extends U>> mapper)
FlatMaps this Traversable.
|
default T |
get(int index)
Returns the element at the specified index.
|
default <C> Map<C,List<T>> |
groupBy(Function<? super T,? extends C> classifier)
Groups this elements by classifying the elements.
|
default Iterator<List<T>> |
grouped(long size)
Groups this
Traversable into fixed size blocks. |
default boolean |
hasDefiniteSize()
Checks if this Traversable is known to have a finite size.
|
default int |
indexOf(T element,
int from)
Returns the index of the first occurrence of the given element after or at some start index
or -1 if this does not contain the given element.
|
default List<T> |
init()
Dual of Traversable.tail(), returning all elements except the last.
|
default Option<List<T>> |
initOption()
Dual of Traversable.tailOption(), returning all elements except the last as
Option . |
default List<T> |
insert(int index,
T element)
Inserts the given element at the specified index.
|
default List<T> |
insertAll(int index,
Iterable<? extends T> elements)
Inserts the given elements at the specified index.
|
default List<T> |
intersperse(T element)
Inserts an element between all elements of this Traversable.
|
boolean |
isEmpty()
Checks if this Traversable is empty.
|
default boolean |
isTraversableAgain()
Checks if this Traversable can be repeatedly traversed.
|
default int |
lastIndexOf(T element,
int end)
Returns the index of the last occurrence of the given element before or at a given end index
or -1 if this does not contain the given element.
|
int |
length()
Computes the number of elements of this Traversable.
|
default <U> List<U> |
map(Function<? super T,? extends U> mapper)
Maps the elements of this
Traversable to elements of a new type preserving their order, if any. |
static <T> List<T> |
narrow(List<? extends T> list)
Narrows a widened
List<? extends T> to List<T>
by performing a type safe-cast. |
static <T> List<T> |
of(T... elements)
Creates a List of the given elements.
|
static <T> List<T> |
of(T element)
Returns a singleton
List , i.e. |
static List<Boolean> |
ofAll(boolean[] array)
Creates a List based on the elements of a boolean array.
|
static List<Byte> |
ofAll(byte[] array)
Creates a List based on the elements of a byte array.
|
static List<Character> |
ofAll(char[] array)
Creates a List based on the elements of a char array.
|
static List<Double> |
ofAll(double[] array)
Creates a List based on the elements of a double array.
|
static List<Float> |
ofAll(float[] array)
Creates a List based on the elements of a float array.
|
static List<Integer> |
ofAll(int[] array)
Creates a List based on the elements of an int array.
|
static <T> List<T> |
ofAll(Iterable<? extends T> elements)
Creates a List of the given elements.
|
static List<Long> |
ofAll(long[] array)
Creates a List based on the elements of a long array.
|
static List<Short> |
ofAll(short[] array)
Creates a List based on the elements of a short array.
|
default List<T> |
padTo(int length,
T element)
A copy of this sequence with an element appended until a given target length is reached.
|
default Tuple2<List<T>,List<T>> |
partition(Predicate<? super T> predicate)
Creates a partition of this
Traversable by splitting this elements in two in distinct tarversables
according to a predicate. |
default List<T> |
patch(int from,
Iterable<? extends T> that,
int replaced)
Produces a new list where a slice of elements in this list is replaced by another sequence.
|
default T |
peek()
Returns the head element without modifying the Stack.
|
default List<T> |
peek(Consumer<? super T> action)
Performs an action on the head element of this
List . |
default Option<T> |
peekOption()
Returns the head element without modifying the Stack.
|
default List<List<T>> |
permutations()
Computes all unique permutations.
|
default List<T> |
pop()
Removes the head element from this Stack.
|
default Tuple2<T,List<T>> |
pop2()
Removes the head element from this Stack.
|
default Option<Tuple2<T,List<T>>> |
pop2Option()
Removes the head element from this Stack.
|
default Option<List<T>> |
popOption()
Removes the head element from this Stack.
|
default List<T> |
prepend(T element)
Prepends an element to this.
|
default List<T> |
prependAll(Iterable<? extends T> elements)
Prepends all given elements to this.
|
default List<T> |
push(T... elements)
Pushes the given elements on top of this Stack.
|
default List<T> |
push(T element)
Pushes a new element on top of this Stack.
|
default List<T> |
pushAll(Iterable<T> elements)
Pushes the given elements on top of this Stack.
|
static List<Character> |
range(char from,
char toExclusive) |
static List<Integer> |
range(int from,
int toExclusive)
Creates a List of int numbers starting from
from , extending to toExclusive - 1 . |
static List<Long> |
range(long from,
long toExclusive)
Creates a List of long numbers starting from
from , extending to toExclusive - 1 . |
static List<Character> |
rangeBy(char from,
char toExclusive,
int step) |
static List<Double> |
rangeBy(double from,
double toExclusive,
double step) |
static List<Integer> |
rangeBy(int from,
int toExclusive,
int step)
Creates a List of int numbers starting from
from , extending to toExclusive - 1 ,
with step . |
static List<Long> |
rangeBy(long from,
long toExclusive,
long step)
Creates a List of long numbers starting from
from , extending to toExclusive - 1 ,
with step . |
static List<Character> |
rangeClosed(char from,
char toInclusive) |
static List<Integer> |
rangeClosed(int from,
int toInclusive)
Creates a List of int numbers starting from
from , extending to toInclusive . |
static List<Long> |
rangeClosed(long from,
long toInclusive)
Creates a List of long numbers starting from
from , extending to toInclusive . |
static List<Character> |
rangeClosedBy(char from,
char toInclusive,
int step) |
static List<Double> |
rangeClosedBy(double from,
double toInclusive,
double step) |
static List<Integer> |
rangeClosedBy(int from,
int toInclusive,
int step)
Creates a List of int numbers starting from
from , extending to toInclusive ,
with step . |
static List<Long> |
rangeClosedBy(long from,
long toInclusive,
long step)
Creates a List of long numbers starting from
from , extending to toInclusive ,
with step . |
default List<T> |
remove(T element)
Removes the first occurrence of the given element.
|
default List<T> |
removeAll(Iterable<? extends T> elements)
Removes all occurrences of the given elements.
|
default List<T> |
removeAll(T removed)
Removes all occurrences of the given element.
|
default List<T> |
removeAt(int index)
Removes the element at the specified position in this sequence.
|
default List<T> |
removeFirst(Predicate<T> predicate)
Removes the first occurrence that satisfy predicate
|
default List<T> |
removeLast(Predicate<T> predicate)
Removes the last occurrence that satisfy predicate
|
default List<T> |
replace(T currentElement,
T newElement)
Replaces the first occurrence (if exists) of the given currentElement with newElement.
|
default List<T> |
replaceAll(T currentElement,
T newElement)
Replaces all occurrences of the given currentElement with newElement.
|
default List<T> |
retainAll(Iterable<? extends T> elements)
Keeps all occurrences of the given elements from this.
|
default List<T> |
reverse()
Reverses the order of elements.
|
default List<T> |
scan(T zero,
BiFunction<? super T,? super T,? extends T> operation)
Computes a prefix scan of the elements of the collection.
|
default <U> List<U> |
scanLeft(U zero,
BiFunction<? super U,? super T,? extends U> operation)
Produces a collection containing cumulative results of applying the
operator going left to right.
|
default <U> List<U> |
scanRight(U zero,
BiFunction<? super T,? super U,? extends U> operation)
Produces a collection containing cumulative results of applying the
operator going right to left.
|
default List<T> |
slice(long beginIndex,
long endIndex)
Returns a Seq that is a slice of this.
|
default Iterator<List<T>> |
sliding(long size)
Slides a window of a specific
size and step size 1 over this Traversable by calling
Traversable.sliding(long, long) . |
default Iterator<List<T>> |
sliding(long size,
long step)
Slides a window of a specific
size and step size over this Traversable . |
default <U> List<T> |
sortBy(Comparator<? super U> comparator,
Function<? super T,? extends U> mapper)
Sorts this elements by comparing the elements in a different domain, using the given
mapper . |
default <U extends Comparable<? super U>> |
sortBy(Function<? super T,? extends U> mapper)
Sorts this elements by comparing the elements in a different domain, using the given
mapper . |
default List<T> |
sorted()
Sorts this elements according to their natural order.
|
default List<T> |
sorted(Comparator<? super T> comparator)
Sorts this elements according to the provided
Comparator . |
default Tuple2<List<T>,List<T>> |
span(Predicate<? super T> predicate)
Returns a tuple where the first element is the longest prefix of elements that satisfy the given
predicate and the second element is the remainder. |
default Tuple2<List<T>,List<T>> |
splitAt(long n)
Splits a Seq at the specified index.
|
default Tuple2<List<T>,List<T>> |
splitAt(Predicate<? super T> predicate)
Splits a sequence at the first element which satisfies the
Predicate , e.g. |
default Tuple2<List<T>,List<T>> |
splitAtInclusive(Predicate<? super T> predicate)
Splits a sequence at the first element which satisfies the
Predicate , e.g. |
default Spliterator<T> |
spliterator() |
default String |
stringPrefix()
Returns the name of this Value type, which is used by toString().
|
default List<T> |
subSequence(int beginIndex)
Returns a Seq that is a subsequence of this.
|
default List<T> |
subSequence(int beginIndex,
int endIndex)
Returns a Seq that is a subsequence of this.
|
static <T> List<T> |
tabulate(int n,
Function<? super Integer,? extends T> f)
Returns a List containing
n values of a given Function f
over a range of integer values from 0 to n - 1 . |
List<T> |
tail()
Drops the first element of a non-empty Traversable.
|
default Option<List<T>> |
tailOption()
Drops the first element of a non-empty Traversable and returns an
Option . |
default List<T> |
take(long n)
Takes the first n elements of this or all elements, if this length < n.
|
default List<T> |
takeRight(long n)
Takes the last n elements of this or all elements, if this length < n.
|
default List<T> |
takeUntil(Predicate<? super T> predicate)
Takes elements until the predicate holds for the current element.
|
default List<T> |
takeWhile(Predicate<? super T> predicate)
Takes elements while the predicate holds for the current element.
|
default <U> U |
transform(Function<? super List<T>,? extends U> f)
Transforms this
List . |
default <U> List<U> |
unit(Iterable<? extends U> iterable) |
default <T1,T2> Tuple2<List<T1>,List<T2>> |
unzip(Function<? super T,Tuple2<? extends T1,? extends T2>> unzipper)
Unzips this elements by mapping this elements to pairs which are subsequently split into two distinct
sets.
|
default <T1,T2,T3> Tuple3<List<T1>,List<T2>,List<T3>> |
unzip3(Function<? super T,Tuple3<? extends T1,? extends T2,? extends T3>> unzipper)
Unzips this elements by mapping this elements to triples which are subsequently split into three distinct
sets.
|
default List<T> |
update(int index,
T element)
Updates the given element at the specified index.
|
default <U> List<Tuple2<T,U>> |
zip(Iterable<? extends U> that)
Returns a traversable formed from this traversable and another Iterable collection by combining
corresponding elements in pairs.
|
default <U> List<Tuple2<T,U>> |
zipAll(Iterable<? extends U> that,
T thisElem,
U thatElem)
Returns a traversable formed from this traversable and another Iterable by combining corresponding elements in
pairs.
|
default List<Tuple2<T,Long>> |
zipWithIndex()
Zips this traversable with its indices.
|
indexWhere, lastIndexOfSlice, lastIndexWhere, narrow, reverseIterator, search, search, segmentLength
apply, containsSlice, crossProduct, crossProduct, endsWith, foldRight, indexOf, indexOfSlice, indexOfSlice, indexWhere, iterator, lastIndexOf, lastIndexOfSlice, lastIndexWhere, narrow, prefixLength, startsWith, startsWith
average, containsAll, count, existsUnique, find, findLast, foldLeft, get, hash, head, headOption, isSingleValued, iterator, last, lastOption, max, maxBy, maxBy, min, minBy, minBy, mkString, mkString, mkString, narrow, nonEmpty, product, reduceLeft, reduceLeftOption, reduceRight, reduceRightOption, size, sum
fold, reduce, reduceOption
contains, corresponds, eq, equals, exists, forAll, forEach, getOption, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, hashCode, narrow, out, out, stderr, stdout, toArray, toCharSeq, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaOptional, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toList, toMap, toOption, toQueue, toRight, toRight, toSet, toStack, toStream, toString, toTree, toTry, toTry, toVector
andThen, arity, compose, curried, identity, lift, memoized, reversed, tupled
isMemoized
static final long serialVersionUID
static <T> Collector<T,ArrayList<T>,List<T>> collector()
Collector
which may be used in conjunction with
Stream.collect(java.util.stream.Collector)
to obtain a List
.T
- Component type of the List.static <T> List<T> empty()
Nil.instance()
.
Note: this method intentionally returns type List
and not Nil
. This comes handy when folding.
If you explicitly need type Nil
use List.Nil.instance().
T
- Component type of Nil, determined by type inference in the particular context.boolean isEmpty()
Traversable
static <T> List<T> narrow(List<? extends T> list)
List<? extends T>
to List<T>
by performing a type safe-cast. This is eligible because immutable/read-only
collections are covariant.T
- Component type of the List
.list
- A List
.list
instance as narrowed type List<T>
.static <T> List<T> of(T element)
List
, i.e. a List
of one element.@SafeVarargs static <T> List<T> of(T... elements)
List.of(1, 2, 3, 4)
= Nil.instance().prepend(4).prepend(3).prepend(2).prepend(1)
= new Cons(1, new Cons(2, new Cons(3, new Cons(4, Nil.instance()))))
T
- Component type of the List.elements
- Zero or more elements.NullPointerException
- if elements
is nullstatic <T> List<T> ofAll(Iterable<? extends T> elements)
The resulting list has the same iteration order as the given iterable of elements if the iteration order of the elements is stable.
T
- Component type of the List.elements
- An Iterable of elements.NullPointerException
- if elements
is nullstatic List<Boolean> ofAll(boolean[] array)
array
- a boolean arraystatic List<Byte> ofAll(byte[] array)
array
- a byte arraystatic List<Character> ofAll(char[] array)
array
- a char arraystatic List<Double> ofAll(double[] array)
array
- a double arraystatic List<Float> ofAll(float[] array)
array
- a float arraystatic List<Integer> ofAll(int[] array)
array
- an int arraystatic List<Long> ofAll(long[] array)
array
- a long arraystatic List<Short> ofAll(short[] array)
array
- a short arraystatic <T> List<T> tabulate(int n, Function<? super Integer,? extends T> f)
n
values of a given Function f
over a range of integer values from 0 to n - 1
.T
- Component type of the Listn
- The number of elements in the Listf
- The Function computing element valuesf(0),f(1), ..., f(n - 1)
NullPointerException
- if f
is nullstatic <T> List<T> fill(int n, Supplier<? extends T> s)
n
values supplied by a given Supplier s
.T
- Component type of the Listn
- The number of elements in the Lists
- The Supplier computing element valuesn
, where each element contains the result supplied by s
.NullPointerException
- if s
is nullstatic List<Integer> range(int from, int toExclusive)
from
, extending to toExclusive - 1
.
Examples:
List.range(0, 0) // = List()
List.range(2, 0) // = List()
List.range(-2, 2) // = List(-2, -1, 0, 1)
from
- the first numbertoExclusive
- the last number + 1from >= toExclusive
static List<Integer> rangeBy(int from, int toExclusive, int step)
from
, extending to toExclusive - 1
,
with step
.
Examples:
List.rangeBy(1, 3, 1) // = List(1, 2)
List.rangeBy(1, 4, 2) // = List(1, 3)
List.rangeBy(4, 1, -2) // = List(4, 2)
List.rangeBy(4, 1, 2) // = List()
from
- the first numbertoExclusive
- the last number + 1step
- the stepfrom >= toInclusive
and step > 0
orfrom <= toInclusive
and step < 0
IllegalArgumentException
- if step
is zerostatic List<Long> range(long from, long toExclusive)
from
, extending to toExclusive - 1
.
Examples:
List.range(0L, 0L) // = List()
List.range(2L, 0L) // = List()
List.range(-2L, 2L) // = List(-2L, -1L, 0L, 1L)
from
- the first numbertoExclusive
- the last number + 1from >= toExclusive
static List<Long> rangeBy(long from, long toExclusive, long step)
from
, extending to toExclusive - 1
,
with step
.
Examples:
List.rangeBy(1L, 3L, 1L) // = List(1L, 2L)
List.rangeBy(1L, 4L, 2L) // = List(1L, 3L)
List.rangeBy(4L, 1L, -2L) // = List(4L, 2L)
List.rangeBy(4L, 1L, 2L) // = List()
from
- the first numbertoExclusive
- the last number + 1step
- the stepfrom >= toInclusive
and step > 0
orfrom <= toInclusive
and step < 0
IllegalArgumentException
- if step
is zerostatic List<Integer> rangeClosed(int from, int toInclusive)
from
, extending to toInclusive
.
Examples:
List.rangeClosed(0, 0) // = List(0)
List.rangeClosed(2, 0) // = List()
List.rangeClosed(-2, 2) // = List(-2, -1, 0, 1, 2)
from
- the first numbertoInclusive
- the last numberfrom > toInclusive
static List<Integer> rangeClosedBy(int from, int toInclusive, int step)
from
, extending to toInclusive
,
with step
.
Examples:
List.rangeClosedBy(1, 3, 1) // = List(1, 2, 3)
List.rangeClosedBy(1, 4, 2) // = List(1, 3)
List.rangeClosedBy(4, 1, -2) // = List(4, 2)
List.rangeClosedBy(4, 1, 2) // = List()
from
- the first numbertoInclusive
- the last numberstep
- the stepfrom > toInclusive
and step > 0
orfrom < toInclusive
and step < 0
IllegalArgumentException
- if step
is zerostatic List<Long> rangeClosed(long from, long toInclusive)
from
, extending to toInclusive
.
Examples:
List.rangeClosed(0L, 0L) // = List(0L)
List.rangeClosed(2L, 0L) // = List()
List.rangeClosed(-2L, 2L) // = List(-2L, -1L, 0L, 1L, 2L)
from
- the first numbertoInclusive
- the last numberfrom > toInclusive
static List<Long> rangeClosedBy(long from, long toInclusive, long step)
from
, extending to toInclusive
,
with step
.
Examples:
List.rangeClosedBy(1L, 3L, 1L) // = List(1L, 2L, 3L)
List.rangeClosedBy(1L, 4L, 2L) // = List(1L, 3L)
List.rangeClosedBy(4L, 1L, -2L) // = List(4L, 2L)
List.rangeClosedBy(4L, 1L, 2L) // = List()
from
- the first numbertoInclusive
- the last numberstep
- the stepfrom > toInclusive
and step > 0
orfrom < toInclusive
and step < 0
IllegalArgumentException
- if step
is zerodefault List<T> append(T element)
Seq
default List<T> appendAll(Iterable<? extends T> elements)
Seq
default List<List<T>> combinations()
Seq
Examples:
[].combinations() = [[]]
[1,2,3].combinations() = [
[], // k = 0
[1], [2], [3], // k = 1
[1,2], [1,3], [2,3], // k = 2
[1,2,3] // k = 3
]
combinations
in interface LinearSeq<T>
combinations
in interface Seq<T>
default List<List<T>> combinations(int k)
Seq
combinations
in interface LinearSeq<T>
combinations
in interface Seq<T>
k
- Size of subsetsdefault Iterator<List<T>> crossProduct(int power)
Seq
Example:
// = ((A,A), (A,B), (A,C), ..., (B,A), (B,B), ..., (Z,Y), (Z,Z))
CharSeq.rangeClosed('A', 'Z').crossProduct(2);
crossProduct
in interface LinearSeq<T>
crossProduct
in interface Seq<T>
power
- the number of cartesian multiplicationsdefault List<T> distinct()
Traversable
equals
.default List<T> distinctBy(Comparator<? super T> comparator)
Traversable
comparator
.distinctBy
in interface LinearSeq<T>
distinctBy
in interface Seq<T>
distinctBy
in interface Traversable<T>
comparator
- A comparatorTraversable
containing this elements without duplicatesdefault <U> List<T> distinctBy(Function<? super T,? extends U> keyExtractor)
Traversable
equals
.
The elements of the result are determined in the order of their occurrence - first match wins.
distinctBy
in interface LinearSeq<T>
distinctBy
in interface Seq<T>
distinctBy
in interface Traversable<T>
U
- key typekeyExtractor
- A key extractorTraversable
containing this elements without duplicatesdefault List<T> drop(long n)
Traversable
drop
in interface LinearSeq<T>
drop
in interface Seq<T>
drop
in interface Traversable<T>
n
- The number of elements to drop.default List<T> dropRight(long n)
Traversable
dropRight
in interface LinearSeq<T>
dropRight
in interface Seq<T>
dropRight
in interface Traversable<T>
n
- The number of elements to drop.default List<T> dropUntil(Predicate<? super T> predicate)
Traversable
Note: This is essentially the same as dropWhile(predicate.negate())
. It is intended to be used with
method references, which cannot be negated directly.
dropUntil
in interface LinearSeq<T>
dropUntil
in interface Seq<T>
dropUntil
in interface Traversable<T>
predicate
- A condition tested subsequently for this elements.default List<T> dropWhile(Predicate<? super T> predicate)
Traversable
dropWhile
in interface LinearSeq<T>
dropWhile
in interface Seq<T>
dropWhile
in interface Traversable<T>
predicate
- A condition tested subsequently for this elements starting with the first.default List<T> filter(Predicate<? super T> predicate)
Traversable
default <U> List<U> flatMap(Function<? super T,? extends Iterable<? extends U>> mapper)
Traversable
default T get(int index)
Seq
default <C> Map<C,List<T>> groupBy(Function<? super T,? extends C> classifier)
Traversable
groupBy
in interface LinearSeq<T>
groupBy
in interface Seq<T>
groupBy
in interface Traversable<T>
C
- classified class typeclassifier
- A function which classifies elements into classesdefault Iterator<List<T>> grouped(long size)
Traversable
Traversable
into fixed size blocks.
Let length be the length of this Iterable. Then grouped is defined as follows:
this.isEmpty()
, the resulting Iterator
is empty.size <= length
, the resulting Iterator
will contain length / size
blocks of size
size
and maybe a non-empty block of size length % size
, if there are remaining elements.size > length
, the resulting Iterator
will contain one block of size length
.
[].grouped(1) = []
[].grouped(0) throws
[].grouped(-1) throws
[1,2,3,4].grouped(2) = [[1,2],[3,4]]
[1,2,3,4,5].grouped(2) = [[1,2],[3,4],[5]]
[1,2,3,4].grouped(5) = [[1,2,3,4]]
Please note that grouped(int)
is a special case of Traversable.sliding(long, long), i.e.
grouped(size)
is the same as sliding(size, size)
.default boolean hasDefiniteSize()
Traversable
This method should be implemented by classes only, i.e. not by interfaces.
hasDefiniteSize
in interface Traversable<T>
default int indexOf(T element, int from)
Seq
default List<T> init()
Traversable
default Option<List<T>> initOption()
Traversable
Option
.initOption
in interface LinearSeq<T>
initOption
in interface Seq<T>
initOption
in interface Traversable<T>
Some(traversable)
or None
if this is empty.int length()
Traversable
Same as Traversable.size()
.
length
in interface Traversable<T>
default List<T> insert(int index, T element)
Seq
default List<T> insertAll(int index, Iterable<? extends T> elements)
Seq
default List<T> intersperse(T element)
Seq
intersperse
in interface LinearSeq<T>
intersperse
in interface Seq<T>
element
- An element.default boolean isTraversableAgain()
Traversable
This method should be implemented by classes only, i.e. not by interfaces.
isTraversableAgain
in interface Traversable<T>
default int lastIndexOf(T element, int end)
Seq
lastIndexOf
in interface Seq<T>
element
- an elementend
- the end indexdefault <U> List<U> map(Function<? super T,? extends U> mapper)
Traversable
Traversable
to elements of a new type preserving their order, if any.default List<T> padTo(int length, T element)
Seq
padTo
in interface LinearSeq<T>
padTo
in interface Seq<T>
length
- the target lengthelement
- the padding elementelement
so that the resulting sequence has a length of at least length
.default List<T> patch(int from, Iterable<? extends T> that, int replaced)
Seq
default Tuple2<List<T>,List<T>> partition(Predicate<? super T> predicate)
Traversable
Traversable
by splitting this elements in two in distinct tarversables
according to a predicate.partition
in interface LinearSeq<T>
partition
in interface Seq<T>
partition
in interface Traversable<T>
predicate
- A predicate which classifies an element if it is in the first or the second traversable.Traversable
contains all elements that satisfy the given predicate
, the second Traversable
contains all elements that don't. The original order of elements is preserved.default T peek()
Stack
default Option<T> peekOption()
Stack
peekOption
in interface Stack<T>
None
if this Stack is empty, otherwise a Some
containing the head elementdefault List<T> peek(Consumer<? super T> action)
List
.default List<List<T>> permutations()
Seq
Example:
[].permutations() = []
[1,2,3].permutations() = [
[1,2,3],
[1,3,2],
[2,1,3],
[2,3,1],
[3,1,2],
[3,2,1]
]
permutations
in interface LinearSeq<T>
permutations
in interface Seq<T>
default List<T> pop()
Stack
default Option<List<T>> popOption()
Stack
default Tuple2<T,List<T>> pop2()
Stack
default Option<Tuple2<T,List<T>>> pop2Option()
Stack
pop2Option
in interface Stack<T>
None
if this Stack is empty, otherwise Some
Tuple
containing the head element and the remaining elements of this Stackdefault List<T> prepend(T element)
Seq
default List<T> prependAll(Iterable<? extends T> elements)
Seq
prependAll
in interface LinearSeq<T>
prependAll
in interface Seq<T>
elements
- An Iterable of elementsdefault List<T> push(T element)
Stack
default List<T> push(T... elements)
Stack
default List<T> pushAll(Iterable<T> elements)
Stack
default List<T> remove(T element)
Seq
default List<T> removeFirst(Predicate<T> predicate)
Seq
removeFirst
in interface LinearSeq<T>
removeFirst
in interface Seq<T>
predicate
- an predicatedefault List<T> removeLast(Predicate<T> predicate)
Seq
removeLast
in interface LinearSeq<T>
removeLast
in interface Seq<T>
predicate
- an predicatedefault List<T> removeAt(int index)
Seq
default List<T> removeAll(T removed)
Seq
default List<T> removeAll(Iterable<? extends T> elements)
Seq
default List<T> replace(T currentElement, T newElement)
Traversable
replace
in interface LinearSeq<T>
replace
in interface Seq<T>
replace
in interface Traversable<T>
currentElement
- An element to be substituted.newElement
- A replacement for currentElement.default List<T> replaceAll(T currentElement, T newElement)
Traversable
replaceAll
in interface LinearSeq<T>
replaceAll
in interface Seq<T>
replaceAll
in interface Traversable<T>
currentElement
- An element to be substituted.newElement
- A replacement for currentElement.default List<T> retainAll(Iterable<? extends T> elements)
Traversable
default List<T> reverse()
Seq
default List<T> scan(T zero, BiFunction<? super T,? super T,? extends T> operation)
Traversable
scan
in interface LinearSeq<T>
scan
in interface Seq<T>
scan
in interface Traversable<T>
zero
- neutral element for the operator opoperation
- the associative operator for the scandefault <U> List<U> scanLeft(U zero, BiFunction<? super U,? super T,? extends U> operation)
Traversable
scanLeft
in interface LinearSeq<T>
scanLeft
in interface Seq<T>
scanLeft
in interface Traversable<T>
U
- the type of the elements in the resulting collectionzero
- the initial valueoperation
- the binary operator applied to the intermediate result and the elementdefault <U> List<U> scanRight(U zero, BiFunction<? super T,? super U,? extends U> operation)
Traversable
scanRight
in interface LinearSeq<T>
scanRight
in interface Seq<T>
scanRight
in interface Traversable<T>
U
- the type of the elements in the resulting collectionzero
- the initial valueoperation
- the binary operator applied to the intermediate result and the elementdefault List<T> slice(long beginIndex, long endIndex)
Seq
beginIndex
and extends to the element at index endIndex - 1
.
Examples:
List.of(1, 2, 3, 4).slice(1, 3); // = (2, 3)
List.of(1, 2, 3, 4).slice(0, 4); // = (1, 2, 3, 4)
List.of(1, 2, 3, 4).slice(2, 2); // = ()
List.of(1, 2).slice(1, 0); // = ()
List.of(1, 2).slice(-10, 10); // = (1, 2)
See also Seq.subSequence(int, int)
which throws in some cases instead of returning a sequence.default Iterator<List<T>> sliding(long size)
Traversable
size
and step size 1 over this Traversable
by calling
Traversable.sliding(long, long)
.default Iterator<List<T>> sliding(long size, long step)
Traversable
size
and step
size over this Traversable
.
Examples:
[].sliding(1,1) = []
[1,2,3,4,5].sliding(2,3) = [[1,2],[4,5]]
[1,2,3,4,5].sliding(2,4) = [[1,2],[5]]
[1,2,3,4,5].sliding(2,5) = [[1,2]]
[1,2,3,4].sliding(5,3) = [[1,2,3,4],[4]]
default List<T> sorted()
Seq
Comparable
, a java.lang.ClassCastException
may be thrown.default List<T> sorted(Comparator<? super T> comparator)
Seq
Comparator
. If this elements are not
Comparable
, a java.lang.ClassCastException
may be thrown.default <U extends Comparable<? super U>> List<T> sortBy(Function<? super T,? extends U> mapper)
Seq
mapper
.default <U> List<T> sortBy(Comparator<? super U> comparator, Function<? super T,? extends U> mapper)
Seq
mapper
.default Tuple2<List<T>,List<T>> span(Predicate<? super T> predicate)
Traversable
predicate
and the second element is the remainder.default Tuple2<List<T>,List<T>> splitAt(long n)
Seq
splitAt(n)
is equivalent to
Tuple.of(take(n), drop(n))
.default Tuple2<List<T>,List<T>> splitAt(Predicate<? super T> predicate)
Seq
Predicate
, e.g. Tuple(init, element+tail).default Tuple2<List<T>,List<T>> splitAtInclusive(Predicate<? super T> predicate)
Seq
Predicate
, e.g. Tuple(init+element, tail).splitAtInclusive
in interface Seq<T>
predicate
- An predicateTuple
containing divided sequencesdefault Spliterator<T> spliterator()
spliterator
in interface Iterable<T>
default String stringPrefix()
Value
stringPrefix
in interface Value<T>
default List<T> subSequence(int beginIndex)
Seq
beginIndex
and extends to the end of this Seq.
Examples:
List.of(1, 2).subSequence(0); // = (1, 2)
List.of(1, 2).subSequence(1); // = (2)
List.of(1, 2).subSequence(2); // = ()
List.of(1, 2).subSequence(10); // throws IndexOutOfBoundsException
List.of(1, 2).subSequence(-10); // throws IndexOutOfBoundsException
See also Seq.drop(long)
which is similar but does not throw.subSequence
in interface LinearSeq<T>
subSequence
in interface Seq<T>
beginIndex
- the beginning index, inclusivedefault List<T> subSequence(int beginIndex, int endIndex)
Seq
beginIndex
and extends to the element at index endIndex - 1
.
Examples:
List.of(1, 2, 3, 4).subSequence(1, 3); // = (2, 3)
List.of(1, 2, 3, 4).subSequence(0, 4); // = (1, 2, 3, 4)
List.of(1, 2, 3, 4).subSequence(2, 2); // = ()
List.of(1, 2).subSequence(1, 0); // throws IndexOutOfBoundsException
List.of(1, 2).subSequence(-10, 1); // throws IndexOutOfBoundsException
List.of(1, 2).subSequence(0, 10); // throws IndexOutOfBoundsException
See also Seq.slice(long, long)
which returns an empty sequence instead of throwing.subSequence
in interface LinearSeq<T>
subSequence
in interface Seq<T>
beginIndex
- the beginning index, inclusiveendIndex
- the end index, exclusiveList<T> tail()
Traversable
default Option<List<T>> tailOption()
Traversable
Option
.tailOption
in interface LinearSeq<T>
tailOption
in interface Seq<T>
tailOption
in interface Traversable<T>
Some(traversable)
or None
if this is empty.default List<T> take(long n)
Traversable
The result is equivalent to sublist(0, max(0, min(length(), n)))
but does not throw if n < 0
or
n > length()
.
In the case of n < 0
the empty instance is returned, in the case of n > length()
this is returned.
default List<T> takeRight(long n)
Traversable
The result is equivalent to sublist(max(0, min(length(), length() - n)), n)
, i.e. takeRight will not
throw if n < 0
or n > length()
.
In the case of n < 0
the empty instance is returned, in the case of n > length()
this is returned.
takeRight
in interface LinearSeq<T>
takeRight
in interface Seq<T>
takeRight
in interface Traversable<T>
n
- The number of elements to take.default List<T> takeUntil(Predicate<? super T> predicate)
Traversable
Note: This is essentially the same as takeWhile(predicate.negate())
. It is intended to be used with
method references, which cannot be negated directly.
takeUntil
in interface LinearSeq<T>
takeUntil
in interface Seq<T>
takeUntil
in interface Traversable<T>
predicate
- A condition tested subsequently for this elements.default List<T> takeWhile(Predicate<? super T> predicate)
Traversable
takeWhile
in interface LinearSeq<T>
takeWhile
in interface Seq<T>
takeWhile
in interface Traversable<T>
predicate
- A condition tested subsequently for the contained elements.default <U> U transform(Function<? super List<T>,? extends U> f)
List
.U
- Type of transformation resultf
- A transformationU
NullPointerException
- if f
is nulldefault <T1,T2> Tuple2<List<T1>,List<T2>> unzip(Function<? super T,Tuple2<? extends T1,? extends T2>> unzipper)
Traversable
unzip
in interface LinearSeq<T>
unzip
in interface Seq<T>
unzip
in interface Traversable<T>
T1
- 1st element type of a pair returned by unzipperT2
- 2nd element type of a pair returned by unzipperunzipper
- a function which converts elements of this to pairsdefault <T1,T2,T3> Tuple3<List<T1>,List<T2>,List<T3>> unzip3(Function<? super T,Tuple3<? extends T1,? extends T2,? extends T3>> unzipper)
Traversable
unzip3
in interface Seq<T>
unzip3
in interface Traversable<T>
T1
- 1st element type of a triplet returned by unzipperT2
- 2nd element type of a triplet returned by unzipperT3
- 3rd element type of a triplet returned by unzipperunzipper
- a function which converts elements of this to pairsdefault List<T> update(int index, T element)
Seq
default <U> List<Tuple2<T,U>> zip(Iterable<? extends U> that)
Traversable
The length of the returned traversable is the minimum of the lengths of this traversable and that
iterable.
zip
in interface LinearSeq<T>
zip
in interface Seq<T>
zip
in interface Traversable<T>
U
- The type of the second half of the returned pairs.that
- The Iterable providing the second half of each result pair.that
iterable.default <U> List<Tuple2<T,U>> zipAll(Iterable<? extends U> that, T thisElem, U thatElem)
Traversable
The length of the returned traversable is the maximum of the lengths of this traversable and that
iterable.
Special case: if this traversable is shorter than that elements, and that elements contains duplicates, the resulting traversable may be shorter than the maximum of the lengths of this and that because a traversable contains an element at most once.
If this Traversable is shorter than that, thisElem values are used to fill the result. If that is shorter than this Traversable, thatElem values are used to fill the result.
zipAll
in interface LinearSeq<T>
zipAll
in interface Seq<T>
zipAll
in interface Traversable<T>
U
- The type of the second half of the returned pairs.that
- The Iterable providing the second half of each result pair.thisElem
- The element to be used to fill up the result if this traversable is shorter than that.thatElem
- The element to be used to fill up the result if that is shorter than this traversable.default List<Tuple2<T,Long>> zipWithIndex()
Traversable
zipWithIndex
in interface LinearSeq<T>
zipWithIndex
in interface Seq<T>
zipWithIndex
in interface Traversable<T>
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