Interface List<T>
- Type Parameters:
T- Component type of the List
- All Superinterfaces:
Foldable<T>, Function<Integer,T>, Function1<Integer, T>, Iterable<T>, LinearSeq<T>, PartialFunction<Integer, T>, Seq<T>, Serializable, Traversable<T>, Value<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 emptyList.List.Cons, which represents aListcontaining one or more elements.
List is a Stack in the sense that it stores elements allowing a last-in-first-out (LIFO) retrieval.
Stack API:
peek()peekOption()pop()popOption()pop2()pop2Option()push(Object)push(Object[])pushAll(Iterable)
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 primarily 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)overpush(Object)prependAll(Iterable)overpushAll(Iterable)tail()overpop()tailOption()overpopOption()
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(1, 2, 3);
List<List<Integer>> s4 = List.ofAll(List.of(1, 2, 3));
List<Integer> s5 = List.ofAll(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.-
Nested Class Summary
Nested Classes -
Field Summary
Fields -
Method Summary
Modifier and TypeMethodDescriptionAppends an element to this.Appends all given elements to this.asJava()Creates an immutableListview on top of thisSeq, i.e.Creates a mutableListview on top of thisSeq, i.e.asJavaMutable(Consumer<? super List<T>> action) default <R> List<R> collect(PartialFunction<? super T, ? extends R> partialFunction) Collects all elements that are in the domain of the givenpartialFunctionby mapping the elements to typeR.Returns aCollectorwhich may be used in conjunction withStream.collect(java.util.stream.Collector)to obtain aList.Returns the union of all combinations from k = 0 to length().combinations(int k) Returns the k-combination of this traversable, i.e.crossProduct(int power) Calculates the n-ary cartesian power (or cross product or simply product) of this.distinct()Returns a new version of this which contains no duplicates.distinctBy(Comparator<? super T> comparator) Returns a new version of this which contains no duplicates.distinctBy(Function<? super T, ? extends U> keyExtractor) Returns a new version of this which contains no duplicates.drop(int n) Drops the first n elements of this or all elements, if this length < n.dropRight(int n) Drops the last n elements of this or all elements, if this length < n.dropRightUntil(Predicate<? super T> predicate) Drops elements until the predicate holds for the current element, starting from the end.dropRightWhile(Predicate<? super T> predicate) Drops elements while the predicate holds for the current element, starting from the end.Drops elements until the predicate holds for the current element.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> Returns a List containingnvalues supplied by a given Suppliers.static <T> List<T> fill(int n, T element) Returns a List containingntimes the givenelementReturns a new traversable consisting of all elements which satisfy the given predicate.default <U> List<U> FlatMaps this Traversable.default Tget(int index) Returns the element at the specified index.Groups this elements by classifying the elements.grouped(int size) Groups thisTraversableinto fixed size blocks.default booleanChecks if this Traversable is known to have a finite size.default intReturns 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.init()Dual of Traversable.tail(), returning all elements except the last.Dual of Traversable.tailOption(), returning all elements except the last asOption.Inserts the given element at the specified index.Inserts the given elements at the specified index.intersperse(T element) Inserts an element between all elements of this Traversable.default booleanisAsync()AListis computed synchronously.booleanisEmpty()Checks if this Traversable is empty.default booleanisLazy()AListis computed eagerly.default booleanChecks if this Traversable can be repeatedly traversed.default Tlast()Dual of Traversable.head(), returning the last element.default intlastIndexOf(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.A copy of this sequence with an element prepended until a given target length is reached.intlength()Computes the number of elements of this Traversable.default <U> List<U> Maps the elements of thisTraversableto elements of a new type preserving their order, if any.static <T> List<T> Narrows a widenedList<? extends T>toList<T>by performing a type-safe cast.static <T> List<T> of(T element) Returns a singletonList, i.e.static <T> List<T> of(T... elements) Creates a List of the given elements.ofAll(boolean... elements) Creates a List from boolean values.ofAll(byte... elements) Creates a List from byte values.ofAll(char... elements) Creates a List from char values.ofAll(double... elements) Creates a List from double values.ofAll(float... elements) Creates a List from float values.ofAll(int... elements) Creates a List from int values.ofAll(long... elements) Creates a List from long values.ofAll(short... elements) Creates a List from short values.static <T> List<T> Creates a List of the given elements.static <T> List<T> Creates a List that contains the elements of the givenStream.Returns thisTraversableif it is nonempty, otherwise return the alternative.Returns thisTraversableif it is nonempty, otherwise return the result of evaluating supplier.A copy of this sequence with an element appended until a given target length is reached.Creates a partition of thisTraversableby splitting this elements in two in distinct traversables according to a predicate.Produces a new list where a slice of elements in this list is replaced by another sequence.default Tpeek()Returns the head element without modifying the List.Performs an action on the head element of thisList.Returns the head element without modifying the List.Computes all unique permutations.pop()Removes the head element from this List.pop2()Removes the head element from this List.Removes the head element from this List.Removes the head element from this List.Prepends an element to this.prependAll(Iterable<? extends T> elements) Prepends all given elements to this.Pushes a new element on top of this List.Pushes the given elements on top of this List.Pushes the given elements on top of this List.range(char from, char toExclusive) range(int from, int toExclusive) Creates a List of int numbers starting fromfrom, extending totoExclusive - 1.range(long from, long toExclusive) Creates a List of long numbers starting fromfrom, extending totoExclusive - 1.rangeBy(char from, char toExclusive, int step) rangeBy(double from, double toExclusive, double step) rangeBy(int from, int toExclusive, int step) Creates a List of int numbers starting fromfrom, extending totoExclusive - 1, withstep.rangeBy(long from, long toExclusive, long step) Creates a List of long numbers starting fromfrom, extending totoExclusive - 1, withstep.rangeClosed(char from, char toInclusive) rangeClosed(int from, int toInclusive) Creates a List of int numbers starting fromfrom, extending totoInclusive.rangeClosed(long from, long toInclusive) Creates a List of long numbers starting fromfrom, extending totoInclusive.rangeClosedBy(char from, char toInclusive, int step) rangeClosedBy(double from, double toInclusive, double step) rangeClosedBy(int from, int toInclusive, int step) Creates a List of int numbers starting fromfrom, extending totoInclusive, withstep.rangeClosedBy(long from, long toInclusive, long step) Creates a List of long numbers starting fromfrom, extending totoInclusive, withstep.Returns a new traversable consisting of all elements which do not satisfy the given predicate.Removes the first occurrence of the given element.Removes all occurrences of the given elements.Deprecated.Removes all occurrences of the given element.removeAt(int index) Removes the element at the specified position in this sequence.removeFirst(Predicate<T> predicate) Removes the first occurrence that satisfy predicateremoveLast(Predicate<T> predicate) Removes the last occurrence that satisfy predicateReplaces the first occurrence (if exists) of the given currentElement with newElement.replaceAll(T currentElement, T newElement) Replaces all occurrences of the given currentElement with newElement.Keeps all occurrences of the given elements from this.reverse()Reverses the order of elements.rotateLeft(int n) Circular rotates the elements by the specified distance to the left direction.rotateRight(int n) Circular rotates the elements by the specified distance to the right direction.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.shuffle()Randomize the order of the elements in the current sequence.slice(int beginIndex, int endIndex) Returns a Seq that is a slice of this.Slides a non-overlapping window of a variable size over thisTraversable.sliding(int size) Slides a window of a specificsizeand step size 1 over thisTraversableby callingTraversable.sliding(int, int).sliding(int size, int step) Slides a window of a specificsizeandstepsize over thisTraversable.sortBy(Comparator<? super U> comparator, Function<? super T, ? extends U> mapper) Sorts this elements by comparing the elements in a different domain, using the givenmapper.default <U extends Comparable<? super U>>
List<T> Sorts this elements by comparing the elements in a different domain, using the givenmapper.sorted()Sorts this elements according to their natural order.sorted(Comparator<? super T> comparator) Sorts this elements according to the providedComparator.Returns a tuple where the first element is the longest prefix of elements that satisfy the givenpredicateand the second element is the remainder.splitAt(int n) Splits a Seq at the specified index.Splits a sequence at the first element which satisfies thePredicate, e.g.splitAtInclusive(Predicate<? super T> predicate) Splits a sequence at the first element which satisfies thePredicate, e.g.default StringReturns the name of this Value type, which is used by toString().subSequence(int beginIndex) Returns a Seq that is a subsequence of this.subSequence(int beginIndex, int endIndex) Returns a Seq that is a subsequence of this.static <T> List<T> Returns a List containingnvalues of a given Functionfover a range of integer values from 0 ton - 1.tail()Drops the first element of a non-empty Traversable.Drops the first element of a non-empty Traversable and returns anOption.take(int n) Takes the first n elements of this or all elements, if this length < n.takeRight(int n) Takes the last n elements of this or all elements, if this length < n.takeRightUntil(Predicate<? super T> predicate) Takes elements until the predicate holds for the current element, starting from the end.takeRightWhile(Predicate<? super T> predicate) Takes elements while the predicate holds for the current element, starting from the end.Takes elements until the predicate holds for the current element.Takes elements while the predicate holds for the current element.default <U> UTransforms thisList.Transposes the rows and columns of aListmatrix.static <T> List<T> Creates a list from a seed value and a function.static <T,U> List <U> unfoldLeft(T seed, Function<? super T, Option<Tuple2<? extends T, ? extends U>>> f) Creates a list from a seed value and a function.static <T,U> List <U> unfoldRight(T seed, Function<? super T, Option<Tuple2<? extends U, ? extends T>>> f) Creates a list from a seed value and a function.Unzips this elements by mapping this elements to pairs which are subsequently split into two distinct sets.Unzips this elements by mapping this elements to triples which are subsequently split into three distinct sets.Updates the given element at the specified index using the specified function.Updates the given element at the specified index.Returns a traversable formed from this traversable and another Iterable collection by combining corresponding elements in pairs.Returns a traversable formed from this traversable and another Iterable by combining corresponding elements in pairs.default <U,R> List <R> zipWith(Iterable<? extends U> that, BiFunction<? super T, ? super U, ? extends R> mapper) Returns a traversable formed from this traversable and another Iterable collection by mapping elements.Zips this traversable with its indices.default <U> List<U> zipWithIndex(BiFunction<? super T, ? super Integer, ? extends U> mapper) Zips this traversable with its indices by applying mapper provided.Methods inherited from interface Foldable
fold, reduce, reduceOptionMethods inherited from interface Function1
andThen, arity, compose, curried, isMemoized, memoized, partial, reversed, tupledMethods inherited from interface LinearSeq
asPartialFunction, indexOfSlice, indexWhere, isDefinedAt, lastIndexOfSlice, lastIndexWhere, reverseIterator, search, search, segmentLengthMethods inherited from interface Seq
apply, containsSlice, crossProduct, crossProduct, endsWith, foldRight, indexOf, indexOfOption, indexOfOption, indexOfSlice, indexOfSliceOption, indexOfSliceOption, indexWhere, indexWhereOption, indexWhereOption, isSequential, iterator, lastIndexOf, lastIndexOfOption, lastIndexOfOption, lastIndexOfSlice, lastIndexOfSliceOption, lastIndexOfSliceOption, lastIndexWhere, lastIndexWhereOption, lastIndexWhereOption, lift, prefixLength, startsWith, startsWith, withDefault, withDefaultValueMethods inherited from interface Traversable
arrangeBy, average, containsAll, count, equals, existsUnique, find, findLast, foldLeft, forEachWithIndex, get, hashCode, head, headOption, isDistinct, isOrdered, isSingleValued, iterator, lastOption, max, maxBy, maxBy, min, minBy, minBy, mkCharSeq, mkCharSeq, mkCharSeq, mkString, mkString, mkString, nonEmpty, product, reduceLeft, reduceLeftOption, reduceRight, reduceRightOption, single, singleOption, size, spliterator, sumMethods inherited from interface Value
collect, collect, contains, corresponds, eq, exists, forAll, forEach, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, getOrNull, out, out, stderr, stdout, toArray, toCharSeq, toCompletableFuture, toEither, toEither, toInvalid, toInvalid, toJavaArray, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaMap, toJavaOptional, toJavaParallelStream, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toLinkedMap, toLinkedMap, toLinkedSet, toList, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toString, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector
-
Field Details
-
serialVersionUID
static final long serialVersionUID- See Also:
-
-
Method Details
-
collector
-
empty
Returns the single instance of Nil. Convenience method forNil.instance().Note: this method intentionally returns type
Listand notNil. This comes handy when folding. If you explicitly need typeNiluse List.Nil.instance().- Type Parameters:
T- Component type of Nil, determined by type inference in the particular context.- Returns:
- The empty list.
-
isAsync
-
isEmpty
boolean isEmpty()Description copied from interface:TraversableChecks if this Traversable is empty. -
isLazy
-
narrow
Narrows a widenedList<? extends T>toList<T>by performing a type-safe cast. This is eligible because immutable/read-only collections are covariant.- Type Parameters:
T- Component type of theList.- Parameters:
list- AList.- Returns:
- the given
listinstance as narrowed typeList<T>.
-
of
Returns a singletonList, i.e. aListof one element.- Type Parameters:
T- The component type- Parameters:
element- An element.- Returns:
- A new List instance containing the given element
-
of
Creates a List of the given 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()))))- Type Parameters:
T- Component type of the List.- Parameters:
elements- Zero or more elements.- Returns:
- A list containing the given elements in the same order.
- Throws:
NullPointerException- ifelementsis null
-
ofAll
Creates a List of the given elements.The resulting list has the same iteration order as the given iterable of elements if the iteration order of the elements is stable.
- Type Parameters:
T- Component type of the List.- Parameters:
elements- An Iterable of elements.- Returns:
- A list containing the given elements in the same order.
- Throws:
NullPointerException- ifelementsis null
-
ofAll
-
ofAll
Creates a List from boolean values.- Parameters:
elements- boolean values- Returns:
- A new List of Boolean values
- Throws:
NullPointerException- if elements is null
-
ofAll
Creates a List from byte values.- Parameters:
elements- byte values- Returns:
- A new List of Byte values
- Throws:
NullPointerException- if elements is null
-
ofAll
Creates a List from char values.- Parameters:
elements- char values- Returns:
- A new List of Character values
- Throws:
NullPointerException- if elements is null
-
ofAll
Creates a List from double values.- Parameters:
elements- double values- Returns:
- A new List of Double values
- Throws:
NullPointerException- if elements is null
-
ofAll
Creates a List from float values.- Parameters:
elements- a float values- Returns:
- A new List of Float values
- Throws:
NullPointerException- if elements is null
-
ofAll
Creates a List from int values.- Parameters:
elements- int values- Returns:
- A new List of Integer values
- Throws:
NullPointerException- if elements is null
-
ofAll
Creates a List from long values.- Parameters:
elements- long values- Returns:
- A new List of Long values
- Throws:
NullPointerException- if elements is null
-
ofAll
Creates a List from short values.- Parameters:
elements- short values- Returns:
- A new List of Short values
- Throws:
NullPointerException- if elements is null
-
tabulate
Returns a List containingnvalues of a given Functionfover a range of integer values from 0 ton - 1.- Type Parameters:
T- Component type of the List- Parameters:
n- The number of elements in the Listf- The Function computing element values- Returns:
- A List consisting of elements
f(0),f(1), ..., f(n - 1) - Throws:
NullPointerException- iffis null
-
fill
Returns a List containingnvalues supplied by a given Suppliers.- Type Parameters:
T- Component type of the List- Parameters:
n- The number of elements in the Lists- The Supplier computing element values- Returns:
- A List of size
n, where each element contains the result supplied bys. - Throws:
NullPointerException- ifsis null
-
fill
Returns a List containingntimes the givenelement- Type Parameters:
T- Component type of the List- Parameters:
n- The number of elements in the Listelement- The element- Returns:
- A List of size
n, where each element is the givenelement.
-
range
-
rangeBy
-
rangeBy
-
range
Creates a List of int numbers starting fromfrom, extending totoExclusive - 1.Examples:
List.range(0, 0) // = List() List.range(2, 0) // = List() List.range(-2, 2) // = List(-2, -1, 0, 1)- Parameters:
from- the first numbertoExclusive- the last number + 1- Returns:
- a range of int values as specified or the empty range if
from >= toExclusive
-
rangeBy
Creates a List of int numbers starting fromfrom, extending totoExclusive - 1, withstep.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()- Parameters:
from- the first numbertoExclusive- the last number + 1step- the step- Returns:
- a range of long values as specified or the empty range if
from >= toInclusiveandstep > 0or
from <= toInclusiveandstep < 0 - Throws:
IllegalArgumentException- ifstepis zero
-
range
Creates a List of long numbers starting fromfrom, extending totoExclusive - 1.Examples:
List.range(0L, 0L) // = List() List.range(2L, 0L) // = List() List.range(-2L, 2L) // = List(-2L, -1L, 0L, 1L)- Parameters:
from- the first numbertoExclusive- the last number + 1- Returns:
- a range of long values as specified or the empty range if
from >= toExclusive
-
rangeBy
Creates a List of long numbers starting fromfrom, extending totoExclusive - 1, withstep.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()- Parameters:
from- the first numbertoExclusive- the last number + 1step- the step- Returns:
- a range of long values as specified or the empty range if
from >= toInclusiveandstep > 0or
from <= toInclusiveandstep < 0 - Throws:
IllegalArgumentException- ifstepis zero
-
rangeClosed
-
rangeClosedBy
-
rangeClosedBy
-
rangeClosed
Creates a List of int numbers starting fromfrom, extending totoInclusive.Examples:
List.rangeClosed(0, 0) // = List(0) List.rangeClosed(2, 0) // = List() List.rangeClosed(-2, 2) // = List(-2, -1, 0, 1, 2)- Parameters:
from- the first numbertoInclusive- the last number- Returns:
- a range of int values as specified or the empty range if
from > toInclusive
-
rangeClosedBy
Creates a List of int numbers starting fromfrom, extending totoInclusive, withstep.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()- Parameters:
from- the first numbertoInclusive- the last numberstep- the step- Returns:
- a range of int values as specified or the empty range if
from > toInclusiveandstep > 0or
from < toInclusiveandstep < 0 - Throws:
IllegalArgumentException- ifstepis zero
-
rangeClosed
Creates a List of long numbers starting fromfrom, extending totoInclusive.Examples:
List.rangeClosed(0L, 0L) // = List(0L) List.rangeClosed(2L, 0L) // = List() List.rangeClosed(-2L, 2L) // = List(-2L, -1L, 0L, 1L, 2L)- Parameters:
from- the first numbertoInclusive- the last number- Returns:
- a range of long values as specified or the empty range if
from > toInclusive
-
rangeClosedBy
Creates a List of long numbers starting fromfrom, extending totoInclusive, withstep.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()- Parameters:
from- the first numbertoInclusive- the last numberstep- the step- Returns:
- a range of int values as specified or the empty range if
from > toInclusiveandstep > 0or
from < toInclusiveandstep < 0 - Throws:
IllegalArgumentException- ifstepis zero
-
transpose
Transposes the rows and columns of aListmatrix.- Type Parameters:
T- matrix element type- Parameters:
matrix- to be transposed.- Returns:
- a transposed
Listmatrix. - Throws:
IllegalArgumentException- if the row lengths ofmatrixdiffer.ex:
List.transpose(List(List(1,2,3), List(4,5,6))) → List(List(1,4), List(2,5), List(3,6))
-
unfoldRight
static <T,U> List<U> unfoldRight(T seed, Function<? super T, Option<Tuple2<? extends U, ? extends T>>> f) Creates a list from a seed value and a function. The function takes the seed at first. The function should returnNonewhen it's done generating the list, otherwiseSomeTupleof the element for the next call and the value to add to the resulting list.Example:
List.unfoldRight(10, x -> x == 0 ? Option.none() : Option.of(new Tuple2<>(x, x-1))); // List(10, 9, 8, 7, 6, 5, 4, 3, 2, 1))- Type Parameters:
T- type of seedsU- type of unfolded values- Parameters:
seed- the start value for the iterationf- the function to get the next step of the iteration- Returns:
- a list with the values built up by the iteration
- Throws:
NullPointerException- iffis null
-
unfoldLeft
static <T,U> List<U> unfoldLeft(T seed, Function<? super T, Option<Tuple2<? extends T, ? extends U>>> f) Creates a list from a seed value and a function. The function takes the seed at first. The function should returnNonewhen it's done generating the list, otherwiseSomeTupleof the value to add to the resulting list and the element for the next call.Example:
List.unfoldLeft(10, x -> x == 0 ? Option.none() : Option.of(new Tuple2<>(x-1, x))); // List(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))- Type Parameters:
T- type of seedsU- type of unfolded values- Parameters:
seed- the start value for the iterationf- the function to get the next step of the iteration- Returns:
- a list with the values built up by the iteration
- Throws:
NullPointerException- iffis null
-
unfold
Creates a list from a seed value and a function. The function takes the seed at first. The function should returnNonewhen it's done generating the list, otherwiseSomeTupleof the value to add to the resulting list and the element for the next call.Example:
List.unfold(10, x -> x == 0 ? Option.none() : Option.of(new Tuple2<>(x-1, x))); // List(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))- Type Parameters:
T- type of seeds and unfolded values- Parameters:
seed- the start value for the iterationf- the function to get the next step of the iteration- Returns:
- a list with the values built up by the iteration
- Throws:
NullPointerException- iffis null
-
append
-
appendAll
Description copied from interface:SeqAppends all given elements to this. -
asJava
Description copied from interface:SeqCreates an immutableListview on top of thisSeq, i.e. calling mutators will result inUnsupportedOperationExceptionat runtime.The difference to conversion methods
toJava*()is that- A view is created in O(1) (constant time) whereas conversion takes O(n) (linear time), with n = collection size.
- The operations on a view have the same performance characteristics than the underlying persistent Vavr collection whereas the performance characteristics of a converted collection are those of the Java standard collections.
java.util.Listview throwsUnsupportedOperationExceptionbefore checking method arguments. Java does handle this case inconsistently.- Specified by:
asJavain interfaceSeq<T>- Returns:
- A new immutable
Collectionview on thisTraversable.
-
asJava
Description copied from interface:Seq -
asJavaMutable
Description copied from interface:SeqCreates a mutableListview on top of thisSeq, i.e. all mutator methods of theListare implemented.- Specified by:
asJavaMutablein interfaceSeq<T>- Returns:
- A new mutable
Collectionview on thisTraversable. - See Also:
-
asJavaMutable
Description copied from interface:Seq- Specified by:
asJavaMutablein interfaceLinearSeq<T>- Specified by:
asJavaMutablein interfaceSeq<T>- Parameters:
action- A side-effecting unit of work that operates on a mutablejava.util.Listview.- Returns:
- this instance, if only read operations are performed on the
java.util.Listview or a new instance of this type, if write operations are performed on thejava.util.Listview. - See Also:
-
collect
Description copied from interface:TraversableCollects all elements that are in the domain of the givenpartialFunctionby mapping the elements to typeR.More specifically, for each of this elements in iteration order first it is checked
If the elements makes it through that filter, the mapped instance is added to the result collectionpartialFunction.isDefinedAt(element)
Note:If thisR newElement = partialFunction.apply(element)Traversableis ordered (i.e. extendsOrdered, the caller ofcollecthas to ensure that the elements are comparable (i.e. extendComparable).- Specified by:
collectin interfaceLinearSeq<T>- Specified by:
collectin interfaceSeq<T>- Specified by:
collectin interfaceTraversable<T>- Type Parameters:
R- The new element type- Parameters:
partialFunction- A function that is not necessarily defined of all elements of this traversable.- Returns:
- A new
Traversableinstance containing elements of typeR
-
combinations
Description copied from interface:SeqReturns the union of all combinations from k = 0 to length().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 ]- Specified by:
combinationsin interfaceLinearSeq<T>- Specified by:
combinationsin interfaceSeq<T>- Returns:
- the combinations of this
-
combinations
Description copied from interface:SeqReturns the k-combination of this traversable, i.e. all subset of this of k distinct elements.- Specified by:
combinationsin interfaceLinearSeq<T>- Specified by:
combinationsin interfaceSeq<T>- Parameters:
k- Size of subsets- Returns:
- the k-combination of this elements
- See Also:
-
crossProduct
Description copied from interface:SeqCalculates the n-ary cartesian power (or cross product or simply product) of this.Example:
// = ((A,A), (A,B), (A,C), ..., (B,A), (B,B), ..., (Z,Y), (Z,Z)) CharSeq.rangeClosed('A', 'Z').crossProduct(2);Cartesian power of negative value will return empty iterator.
Example:
// = () CharSeq.rangeClosed('A', 'Z').crossProduct(-1);- Specified by:
crossProductin interfaceLinearSeq<T>- Specified by:
crossProductin interfaceSeq<T>- Parameters:
power- the number of cartesian multiplications- Returns:
- A new Iterator representing the n-ary cartesian power of this
-
distinct
Description copied from interface:TraversableReturns a new version of this which contains no duplicates. Elements are compared usingequals. -
distinctBy
Description copied from interface:TraversableReturns a new version of this which contains no duplicates. Elements are compared using the givencomparator.- Specified by:
distinctByin interfaceLinearSeq<T>- Specified by:
distinctByin interfaceSeq<T>- Specified by:
distinctByin interfaceTraversable<T>- Parameters:
comparator- A comparator- Returns:
- a new
Traversablecontaining this elements without duplicates
-
distinctBy
Description copied from interface:TraversableReturns a new version of this which contains no duplicates. Elements mapped to keys which are compared usingequals.The elements of the result are determined in the order of their occurrence - first match wins.
- Specified by:
distinctByin interfaceLinearSeq<T>- Specified by:
distinctByin interfaceSeq<T>- Specified by:
distinctByin interfaceTraversable<T>- Type Parameters:
U- key type- Parameters:
keyExtractor- A key extractor- Returns:
- a new
Traversablecontaining this elements without duplicates
-
drop
Description copied from interface:TraversableDrops the first n elements of this or all elements, if this length < n.- Specified by:
dropin interfaceLinearSeq<T>- Specified by:
dropin interfaceSeq<T>- Specified by:
dropin interfaceTraversable<T>- Parameters:
n- The number of elements to drop.- Returns:
- a new instance consisting of all elements of this except the first n ones, or else the empty instance, if this has less than n elements.
-
dropUntil
Description copied from interface:TraversableDrops elements until the predicate holds for the current element.- Specified by:
dropUntilin interfaceLinearSeq<T>- Specified by:
dropUntilin interfaceSeq<T>- Specified by:
dropUntilin interfaceTraversable<T>- Parameters:
predicate- A condition tested subsequently for this elements.- Returns:
- a new instance consisting of all elements starting from the first one which does satisfy the given predicate.
-
dropWhile
Description copied from interface:TraversableDrops elements while the predicate holds for the current element.Note: This is essentially the same as
dropUntil(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.- Specified by:
dropWhilein interfaceLinearSeq<T>- Specified by:
dropWhilein interfaceSeq<T>- Specified by:
dropWhilein interfaceTraversable<T>- Parameters:
predicate- A condition tested subsequently for this elements.- Returns:
- a new instance consisting of all elements starting from the first one which does not satisfy the given predicate.
-
dropRight
Description copied from interface:TraversableDrops the last n elements of this or all elements, if this length < n.- Specified by:
dropRightin interfaceLinearSeq<T>- Specified by:
dropRightin interfaceSeq<T>- Specified by:
dropRightin interfaceTraversable<T>- Parameters:
n- The number of elements to drop.- Returns:
- a new instance consisting of all elements of this except the last n ones, or else the empty instance, if this has less than n elements.
-
dropRightUntil
Description copied from interface:SeqDrops elements until the predicate holds for the current element, starting from the end.- Specified by:
dropRightUntilin interfaceLinearSeq<T>- Specified by:
dropRightUntilin interfaceSeq<T>- Parameters:
predicate- A condition tested subsequently for this elements, starting from the end.- Returns:
- a new instance consisting of all elements until and including the last one which does satisfy the given predicate.
-
dropRightWhile
Description copied from interface:SeqDrops elements while the predicate holds for the current element, starting from the end.Note: This is essentially the same as
dropRightUntil(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.- Specified by:
dropRightWhilein interfaceLinearSeq<T>- Specified by:
dropRightWhilein interfaceSeq<T>- Parameters:
predicate- A condition tested subsequently for this elements, starting from the end.- Returns:
- a new instance consisting of all elements until and including the last one which does not satisfy the given predicate.
-
filter
Description copied from interface:TraversableReturns a new traversable consisting of all elements which satisfy the given predicate. -
reject
Description copied from interface:TraversableReturns a new traversable consisting of all elements which do not satisfy the given predicate.The default implementation is equivalent to
filter(predicate.negate() -
flatMap
Description copied from interface:TraversableFlatMaps this Traversable. -
get
-
groupBy
Description copied from interface:TraversableGroups this elements by classifying the elements.- Specified by:
groupByin interfaceLinearSeq<T>- Specified by:
groupByin interfaceSeq<T>- Specified by:
groupByin interfaceTraversable<T>- Type Parameters:
C- classified class type- Parameters:
classifier- A function which classifies elements into classes- Returns:
- A Map containing the grouped elements
- See Also:
-
grouped
Description copied from interface:TraversableGroups thisTraversableinto fixed size blocks.Let length be the length of this Iterable. Then grouped is defined as follows:
- If
this.isEmpty(), the resultingIteratoris empty. - If
size <= length, the resultingIteratorwill containlength / sizeblocks of sizesizeand maybe a non-empty block of sizelength % size, if there are remaining elements. - If
size > length, the resultingIteratorwill contain one block of sizelength.
Please note that[].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]]grouped(int)is a special case of Traversable.sliding(int, int), i.e.grouped(size)is the same assliding(size, size). - If
-
hasDefiniteSize
default boolean hasDefiniteSize()Description copied from interface:TraversableChecks if this Traversable is known to have a finite size.This method should be implemented by classes only, i.e. not by interfaces.
- Specified by:
hasDefiniteSizein interfaceTraversable<T>- Returns:
- true, if this Traversable is known to have a finite size, false otherwise.
-
indexOf
Description copied from interface:SeqReturns 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. -
init
Description copied from interface:TraversableDual of Traversable.tail(), returning all elements except the last. -
initOption
Description copied from interface:TraversableDual of Traversable.tailOption(), returning all elements except the last asOption.- Specified by:
initOptionin interfaceLinearSeq<T>- Specified by:
initOptionin interfaceSeq<T>- Specified by:
initOptionin interfaceTraversable<T>- Returns:
Some(traversable)orNoneif this is empty.
-
length
int length()Description copied from interface:TraversableComputes the number of elements of this Traversable.Same as
Traversable.size().- Specified by:
lengthin interfaceTraversable<T>- Returns:
- the number of elements
-
insert
Description copied from interface:SeqInserts the given element at the specified index. -
insertAll
Description copied from interface:SeqInserts the given elements at the specified index. -
intersperse
Description copied from interface:SeqInserts an element between all elements of this Traversable.- Specified by:
interspersein interfaceLinearSeq<T>- Specified by:
interspersein interfaceSeq<T>- Parameters:
element- An element.- Returns:
- an interspersed version of this
-
isTraversableAgain
default boolean isTraversableAgain()Description copied from interface:TraversableChecks if this Traversable can be repeatedly traversed.This method should be implemented by classes only, i.e. not by interfaces.
- Specified by:
isTraversableAgainin interfaceTraversable<T>- Returns:
- true, if this Traversable is known to be traversable repeatedly, false otherwise.
-
last
Description copied from interface:TraversableDual of Traversable.head(), returning the last element.- Specified by:
lastin interfaceTraversable<T>- Returns:
- the last element.
-
lastIndexOf
Description copied from interface:SeqReturns 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.- Specified by:
lastIndexOfin interfaceSeq<T>- Parameters:
element- an elementend- the end index- Returns:
- the index of the last occurrence of the given element
-
map
Description copied from interface:TraversableMaps the elements of thisTraversableto elements of a new type preserving their order, if any. -
orElse
Description copied from interface:TraversableReturns thisTraversableif it is nonempty, otherwise return the alternative. -
orElse
Description copied from interface:TraversableReturns thisTraversableif it is nonempty, otherwise return the result of evaluating supplier. -
padTo
Description copied from interface:SeqA copy of this sequence with an element appended until a given target length is reached.Note: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.
- Specified by:
padToin interfaceLinearSeq<T>- Specified by:
padToin interfaceSeq<T>- Parameters:
length- the target lengthelement- the padding element- Returns:
- a new sequence consisting of all elements of this sequence followed by the minimal number
of occurrences of
elementso that the resulting sequence has a length of at leastlength.
-
leftPadTo
Description copied from interface:SeqA copy of this sequence with an element prepended until a given target length is reached.Note: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.
- Specified by:
leftPadToin interfaceSeq<T>- Parameters:
length- the target lengthelement- the padding element- Returns:
- a new sequence consisting of all elements of this sequence prepended by the minimal number
of occurrences of
elementso that the resulting sequence has a length of at leastlength.
-
patch
Description copied from interface:SeqProduces a new list where a slice of elements in this list is replaced by another sequence. -
partition
Description copied from interface:TraversableCreates a partition of thisTraversableby splitting this elements in two in distinct traversables according to a predicate.- Specified by:
partitionin interfaceLinearSeq<T>- Specified by:
partitionin interfaceSeq<T>- Specified by:
partitionin interfaceTraversable<T>- Parameters:
predicate- A predicate which classifies an element if it is in the first or the second traversable.- Returns:
- A disjoint union of two traversables. The first
Traversablecontains all elements that satisfy the givenpredicate, the secondTraversablecontains all elements that don't. The original order of elements is preserved.
-
peek
Returns the head element without modifying the List.- Returns:
- the first element
- Throws:
NoSuchElementException- if this List is empty
-
peekOption
-
peek
Performs an action on the head element of thisList. -
permutations
Description copied from interface:SeqComputes all unique permutations.Example:
[].permutations() = [] [1,2,3].permutations() = [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1] ]- Specified by:
permutationsin interfaceLinearSeq<T>- Specified by:
permutationsin interfaceSeq<T>- Returns:
- this unique permutations
-
pop
Removes the head element from this List.- Returns:
- the elements of this List without the head element
- Throws:
NoSuchElementException- if this List is empty
-
popOption
-
pop2
Removes the head element from this List.- Returns:
- a tuple containing the head element and the remaining elements of this List
- Throws:
NoSuchElementException- if this List is empty
-
pop2Option
-
prepend
Description copied from interface:SeqPrepends an element to this. -
prependAll
Description copied from interface:SeqPrepends all given elements to this.- Specified by:
prependAllin interfaceLinearSeq<T>- Specified by:
prependAllin interfaceSeq<T>- Parameters:
elements- An Iterable of elements- Returns:
- A new Seq containing the given elements prepended to this elements
-
push
-
push
Pushes the given elements on top of this List. A List has LIFO order, i.e. the last of the given elements is the first which will be retrieved.- Parameters:
elements- Elements, may be empty- Returns:
- a new
Listinstance, containing the new elements on top of this List - Throws:
NullPointerException- if elements is null
-
pushAll
Pushes the given elements on top of this List. A List has LIFO order, i.e. the last of the given elements is the first which will be retrieved.- Parameters:
elements- An Iterable of elements, may be empty- Returns:
- a new
Listinstance, containing the new elements on top of this List - Throws:
NullPointerException- if elements is null
-
remove
Description copied from interface:SeqRemoves the first occurrence of the given element. -
removeFirst
-
removeLast
-
removeAt
Description copied from interface:SeqRemoves the element at the specified position in this sequence. Shifts any subsequent elements to the left (subtracts one from their indices). -
removeAll
Description copied from interface:SeqRemoves all occurrences of the given element. -
removeAll
Description copied from interface:SeqRemoves all occurrences of the given elements. -
removeAll
Deprecated.Description copied from interface:SeqReturns a new Seq consisting of all elements which do not satisfy the given predicate. -
replace
Description copied from interface:TraversableReplaces the first occurrence (if exists) of the given currentElement with newElement.- Specified by:
replacein interfaceLinearSeq<T>- Specified by:
replacein interfaceSeq<T>- Specified by:
replacein interfaceTraversable<T>- Parameters:
currentElement- An element to be substituted.newElement- A replacement for currentElement.- Returns:
- a Traversable containing all elements of this where the first occurrence of currentElement is replaced with newElement.
-
replaceAll
Description copied from interface:TraversableReplaces all occurrences of the given currentElement with newElement.- Specified by:
replaceAllin interfaceLinearSeq<T>- Specified by:
replaceAllin interfaceSeq<T>- Specified by:
replaceAllin interfaceTraversable<T>- Parameters:
currentElement- An element to be substituted.newElement- A replacement for currentElement.- Returns:
- a Traversable containing all elements of this where all occurrences of currentElement are replaced with newElement.
-
retainAll
Description copied from interface:TraversableKeeps all occurrences of the given elements from this. -
reverse
-
rotateLeft
Description copied from interface:SeqCircular rotates the elements by the specified distance to the left direction.// = List(3, 4, 5, 1, 2) List.of(1, 2, 3, 4, 5).rotateLeft(2);- Specified by:
rotateLeftin interfaceLinearSeq<T>- Specified by:
rotateLeftin interfaceSeq<T>- Parameters:
n- distance of left rotation- Returns:
- the rotated elements.
-
rotateRight
Description copied from interface:SeqCircular rotates the elements by the specified distance to the right direction.// = List(4, 5, 1, 2, 3) List.of(1, 2, 3, 4, 5).rotateRight(2);- Specified by:
rotateRightin interfaceLinearSeq<T>- Specified by:
rotateRightin interfaceSeq<T>- Parameters:
n- distance of right rotation- Returns:
- the rotated elements.
-
scan
Description copied from interface:TraversableComputes a prefix scan of the elements of the collection. Note: The neutral element z may be applied more than once.- Specified by:
scanin interfaceLinearSeq<T>- Specified by:
scanin interfaceSeq<T>- Specified by:
scanin interfaceTraversable<T>- Parameters:
zero- neutral element for the operator opoperation- the associative operator for the scan- Returns:
- a new traversable collection containing the prefix scan of the elements in this traversable collection
-
scanLeft
Description copied from interface:TraversableProduces a collection containing cumulative results of applying the operator going left to right. Note: will not terminate for infinite-sized collections. Note: might return different results for different runs, unless the underlying collection type is ordered.- Specified by:
scanLeftin interfaceLinearSeq<T>- Specified by:
scanLeftin interfaceSeq<T>- Specified by:
scanLeftin interfaceTraversable<T>- Type Parameters:
U- the type of the elements in the resulting collection- Parameters:
zero- the initial valueoperation- the binary operator applied to the intermediate result and the element- Returns:
- collection with intermediate results
-
scanRight
Description copied from interface:TraversableProduces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result. Note: will not terminate for infinite-sized collections. Note: might return different results for different runs, unless the underlying collection type is ordered.- Specified by:
scanRightin interfaceLinearSeq<T>- Specified by:
scanRightin interfaceSeq<T>- Specified by:
scanRightin interfaceTraversable<T>- Type Parameters:
U- the type of the elements in the resulting collection- Parameters:
zero- the initial valueoperation- the binary operator applied to the intermediate result and the element- Returns:
- collection with intermediate results
-
shuffle
Description copied from interface:SeqRandomize the order of the elements in the current sequence. -
slice
Description copied from interface:SeqReturns a Seq that is a slice of this. The slice begins with the element at the specifiedbeginIndexand extends to the element at indexendIndex - 1.Examples:
See alsoList.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)Seq.subSequence(int, int)which throws in some cases instead of returning a sequence. -
slideBy
Description copied from interface:TraversableSlides a non-overlapping window of a variable size over thisTraversable.Each window contains elements with the same class, as determined by
classifier. Two consecutive values in thisTraversablewill be in the same window only ifclassifierreturns equal values for them. Otherwise, the values will constitute the last element of the previous window and the first element of the next window.Examples:
[].slideBy(Function.identity()) = [] [1,2,3,4,4,5].slideBy(Function.identity()) = [[1],[2],[3],[4,4],[5]] [1,2,3,10,12,5,7,20,29].slideBy(x -> x/10) = [[1,2,3],[10,12],[5,7],[20,29]] -
sliding
Description copied from interface:TraversableSlides a window of a specificsizeand step size 1 over thisTraversableby callingTraversable.sliding(int, int). -
sliding
Description copied from interface:TraversableSlides a window of a specificsizeandstepsize over thisTraversable.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]] -
sorted
Description copied from interface:SeqSorts this elements according to their natural order. If this elements are notComparable, ajava.lang.ClassCastExceptionmay be thrown. -
sorted
Description copied from interface:SeqSorts this elements according to the providedComparator. If this elements are notComparable, ajava.lang.ClassCastExceptionmay be thrown. -
sortBy
Description copied from interface:SeqSorts this elements by comparing the elements in a different domain, using the givenmapper. -
sortBy
-
span
Description copied from interface:TraversableReturns a tuple where the first element is the longest prefix of elements that satisfy the givenpredicateand the second element is the remainder. -
splitAt
Description copied from interface:SeqSplits a Seq at the specified index. The result ofsplitAt(n)is equivalent toTuple.of(take(n), drop(n)). -
splitAt
-
splitAtInclusive
-
stringPrefix
Description copied from interface:ValueReturns the name of this Value type, which is used by toString().- Specified by:
stringPrefixin interfaceValue<T>- Returns:
- This type name.
-
subSequence
Description copied from interface:SeqReturns a Seq that is a subsequence of this. The subsequence begins with the element at the specifiedbeginIndexand extends to the end of this Seq.Examples:
See alsoList.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 IndexOutOfBoundsExceptionSeq.drop(int)which is similar but does not throw.- Specified by:
subSequencein interfaceLinearSeq<T>- Specified by:
subSequencein interfaceSeq<T>- Parameters:
beginIndex- the beginning index, inclusive- Returns:
- the specified subsequence
-
subSequence
Description copied from interface:SeqReturns a Seq that is a subsequence of this. The subsequence begins with the element at the specifiedbeginIndexand extends to the element at indexendIndex - 1.Examples:
See alsoList.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 IndexOutOfBoundsExceptionSeq.slice(int, int)which returns an empty sequence instead of throwing.- Specified by:
subSequencein interfaceLinearSeq<T>- Specified by:
subSequencein interfaceSeq<T>- Parameters:
beginIndex- the beginning index, inclusiveendIndex- the end index, exclusive- Returns:
- the specified subsequence
-
tail
Description copied from interface:TraversableDrops the first element of a non-empty Traversable. -
tailOption
Description copied from interface:TraversableDrops the first element of a non-empty Traversable and returns anOption.- Specified by:
tailOptionin interfaceLinearSeq<T>- Specified by:
tailOptionin interfaceSeq<T>- Specified by:
tailOptionin interfaceTraversable<T>- Returns:
Some(traversable)orNoneif this is empty.
-
take
Description copied from interface:TraversableTakes the first n elements of this or all elements, if this length < n.The result is equivalent to
sublist(0, max(0, min(length(), n)))but does not throw ifn < 0orn > length().In the case of
n < 0the empty instance is returned, in the case ofn > length()this is returned. -
takeUntil
Description copied from interface:TraversableTakes elements until the predicate holds for the current element.Note: This is essentially the same as
takeWhile(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.- Specified by:
takeUntilin interfaceLinearSeq<T>- Specified by:
takeUntilin interfaceSeq<T>- Specified by:
takeUntilin interfaceTraversable<T>- Parameters:
predicate- A condition tested subsequently for this elements.- Returns:
- a new instance consisting of all elements before the first one which does satisfy the given predicate.
-
takeWhile
Description copied from interface:TraversableTakes elements while the predicate holds for the current element.- Specified by:
takeWhilein interfaceLinearSeq<T>- Specified by:
takeWhilein interfaceSeq<T>- Specified by:
takeWhilein interfaceTraversable<T>- Parameters:
predicate- A condition tested subsequently for the contained elements.- Returns:
- a new instance consisting of all elements before the first one which does not satisfy the given predicate.
-
takeRight
Description copied from interface:TraversableTakes the last n elements of this or all elements, if this length < n.The result is equivalent to
sublist(max(0, min(length(), length() - n)), n), i.e. takeRight will not throw ifn < 0orn > length().In the case of
n < 0the empty instance is returned, in the case ofn > length()this is returned.- Specified by:
takeRightin interfaceLinearSeq<T>- Specified by:
takeRightin interfaceSeq<T>- Specified by:
takeRightin interfaceTraversable<T>- Parameters:
n- The number of elements to take.- Returns:
- A new instance consisting of the last n elements of this or all elements, if this has less than n elements.
-
takeRightUntil
Description copied from interface:SeqTakes elements until the predicate holds for the current element, starting from the end.- Specified by:
takeRightUntilin interfaceLinearSeq<T>- Specified by:
takeRightUntilin interfaceSeq<T>- Parameters:
predicate- A condition tested subsequently for this elements, starting from the end.- Returns:
- a new instance consisting of all elements after the last one which does satisfy the given predicate.
-
takeRightWhile
Description copied from interface:SeqTakes elements while the predicate holds for the current element, starting from the end.Note: This is essentially the same as
takeRightUntil(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.- Specified by:
takeRightWhilein interfaceLinearSeq<T>- Specified by:
takeRightWhilein interfaceSeq<T>- Parameters:
predicate- A condition tested subsequently for this elements, starting from the end.- Returns:
- a new instance consisting of all elements after the last one which does not satisfy the given predicate.
-
transform
Transforms thisList.- Type Parameters:
U- Type of transformation result- Parameters:
f- A transformation- Returns:
- An instance of type
U - Throws:
NullPointerException- iffis null
-
unzip
default <T1,T2> Tuple2<List<T1>,List<T2>> unzip(Function<? super T, Tuple2<? extends T1, ? extends T2>> unzipper) Description copied from interface:TraversableUnzips this elements by mapping this elements to pairs which are subsequently split into two distinct sets.- Specified by:
unzipin interfaceLinearSeq<T>- Specified by:
unzipin interfaceSeq<T>- Specified by:
unzipin interfaceTraversable<T>- Type Parameters:
T1- 1st element type of a pair returned by unzipperT2- 2nd element type of a pair returned by unzipper- Parameters:
unzipper- a function which converts elements of this to pairs- Returns:
- A pair of set containing elements split by unzipper
-
unzip3
default <T1,T2, Tuple3<List<T1>,T3> List<T2>, unzip3List<T3>> (Function<? super T, Tuple3<? extends T1, ? extends T2, ? extends T3>> unzipper) Description copied from interface:TraversableUnzips this elements by mapping this elements to triples which are subsequently split into three distinct sets.- Specified by:
unzip3in interfaceSeq<T>- Specified by:
unzip3in interfaceTraversable<T>- Type Parameters:
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 unzipper- Parameters:
unzipper- a function which converts elements of this to pairs- Returns:
- A triplet of set containing elements split by unzipper
-
update
Description copied from interface:SeqUpdates the given element at the specified index. -
update
Description copied from interface:SeqUpdates the given element at the specified index using the specified function. -
zip
Description copied from interface:TraversableReturns a traversable formed from this traversable and another Iterable collection by combining corresponding elements in pairs. If one of the two iterables is longer than the other, its remaining elements are ignored.The length of the returned traversable is the minimum of the lengths of this traversable and
thatiterable.- Specified by:
zipin interfaceLinearSeq<T>- Specified by:
zipin interfaceSeq<T>- Specified by:
zipin interfaceTraversable<T>- Type Parameters:
U- The type of the second half of the returned pairs.- Parameters:
that- The Iterable providing the second half of each result pair.- Returns:
- a new traversable containing pairs consisting of corresponding elements of this traversable and
thatiterable.
-
zipWith
default <U,R> List<R> zipWith(Iterable<? extends U> that, BiFunction<? super T, ? super U, ? extends R> mapper) Description copied from interface:TraversableReturns a traversable formed from this traversable and another Iterable collection by mapping elements. If one of the two iterables is longer than the other, its remaining elements are ignored.The length of the returned traversable is the minimum of the lengths of this traversable and
thatiterable.- Specified by:
zipWithin interfaceLinearSeq<T>- Specified by:
zipWithin interfaceSeq<T>- Specified by:
zipWithin interfaceTraversable<T>- Type Parameters:
U- The type of the second parameter of the mapper.R- The type of the mapped elements.- Parameters:
that- The Iterable providing the second parameter of the mapper.mapper- a mapper.- Returns:
- a new traversable containing mapped elements of this traversable and
thatiterable.
-
zipAll
Description copied from interface:TraversableReturns a traversable formed from this traversable and another Iterable by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.The length of the returned traversable is the maximum of the lengths of this traversable and
thatiterable.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.
- Specified by:
zipAllin interfaceLinearSeq<T>- Specified by:
zipAllin interfaceSeq<T>- Specified by:
zipAllin interfaceTraversable<T>- Type Parameters:
U- The type of the second half of the returned pairs.- Parameters:
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.- Returns:
- A new traversable containing pairs consisting of corresponding elements of this traversable and that.
-
zipWithIndex
Description copied from interface:TraversableZips this traversable with its indices.- Specified by:
zipWithIndexin interfaceLinearSeq<T>- Specified by:
zipWithIndexin interfaceSeq<T>- Specified by:
zipWithIndexin interfaceTraversable<T>- Returns:
- A new traversable containing all elements of this traversable paired with their index, starting with 0.
-
zipWithIndex
Description copied from interface:TraversableZips this traversable with its indices by applying mapper provided.- Specified by:
zipWithIndexin interfaceLinearSeq<T>- Specified by:
zipWithIndexin interfaceSeq<T>- Specified by:
zipWithIndexin interfaceTraversable<T>- Type Parameters:
U- The type of the mapped elements.- Parameters:
mapper- a mapper.- Returns:
- a new traversable containing elements of this traversable, zipped with indices, and mapped with mapper provided.
-