Trait scala.collection.BufferedIterator

trait BufferedIterator[+A] extends Iterator[A]

Buffered iterators are iterators which provide a method head that inspects the next element without discarding it.

Source: BufferedIterator.scala
Since: 2.8
Linear Supertypes: Iterator[A], IterableOnceOps[A, Iterator, Iterator[A]], IterableOnce[A], AnyRef, Any

Type Members

class GroupedIterator[B >: A] extends AbstractIterator[immutable.Seq[B]]

A flexible iterator for transforming an Iterator[A] into an Iterator[Seq[A]], with configurable sequence size, step, and strategy for dealing with elements which don't fit evenly.

Typical uses can be achieved via methods grouped and sliding.

Definition Classes: Iterator

Abstract Value Members

abstract def hasNext: Boolean

Check if there is a next element available.

returns: true if there is a next element, false otherwise

Definition Classes: Iterator
Note: Reuse: The iterator remains valid for further use whatever result is returned.

abstract def head: A

abstract def next(): A

Return the next element and advance the iterator.

returns: the next element.

Definition Classes: Iterator
Annotations: @throws(scala.this.throws.<init>$default$1[NoSuchElementException])
Exceptions thrown: NoSuchElementException if there is no next element.
Note: Reuse: Advances the iterator, which may exhaust the elements. It is valid to make additional calls on the iterator.

Concrete Value Members

final def !=(arg0: Any): Boolean

Test two objects for inequality.

returns: true if !(this == that), false otherwise.

Definition Classes: AnyRef → Any

final def ##(): Int

Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.

returns: a hash value consistent with ==

Definition Classes: AnyRef → Any

def +(other: String): String

Implicit: This member is added by an implicit conversion from BufferedIterator[A] toany2stringadd[BufferedIterator[A]] performed by method any2stringadd in scala.Predef.
Definition Classes: any2stringadd

final def ++[B >: A](xs: => IterableOnce[B]): Iterator[B]

Definition Classes: Iterator
Annotations: @inline()

def ->[B](y: B): (BufferedIterator[A], B)

Implicit: This member is added by an implicit conversion from BufferedIterator[A] toArrowAssoc[BufferedIterator[A]] performed by method ArrowAssoc in scala.Predef.
Definition Classes: ArrowAssoc
Annotations: @inline()

final def ==(arg0: Any): Boolean

The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

returns: true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes: AnyRef → Any

final def addString(b: mutable.StringBuilder): mutable.StringBuilder

Appends all elements of this collection to a string builder. The written text consists of the string representations (w.r.t. the method toString) of all elements of this collection without any separator string.

Example:

scala> val a = List(1,2,3,4)
a: List[Int] = List(1, 2, 3, 4)

scala> val b = new StringBuilder()
b: StringBuilder =

scala> val h = a.addString(b)
h: StringBuilder = 1234

b: the string builder to which elements are appended.
returns: the string builder b to which elements were appended.

Definition Classes: IterableOnceOps
Annotations: @inline()

final def addString(b: mutable.StringBuilder, sep: String): mutable.StringBuilder

Appends all elements of this collection to a string builder using a separator string. The written text consists of the string representations (w.r.t. the method toString) of all elements of this collection, separated by the string sep.

Example:

scala> val a = List(1,2,3,4)
a: List[Int] = List(1, 2, 3, 4)

scala> val b = new StringBuilder()
b: StringBuilder =

scala> a.addString(b, ", ")
res0: StringBuilder = 1, 2, 3, 4

b: the string builder to which elements are appended.
sep: the separator string.
returns: the string builder b to which elements were appended.

Definition Classes: IterableOnceOps
Annotations: @inline()

def addString(b: mutable.StringBuilder, start: String, sep: String, end: String): mutable.StringBuilder

Appends all elements of this collection to a string builder using start, end, and separator strings. The written text begins with the string start and ends with the string end. Inside, the string representations (w.r.t. the method toString) of all elements of this collection are separated by the string sep.

Example:

scala> val a = List(1,2,3,4)
a: List[Int] = List(1, 2, 3, 4)

scala> val b = new StringBuilder()
b: StringBuilder =

scala> a.addString(b , "List(" , ", " , ")")
res5: StringBuilder = List(1, 2, 3, 4)

b: the string builder to which elements are appended.
start: the starting string.
sep: the separator string.
end: the ending string.
returns: the string builder b to which elements were appended.

Definition Classes: IterableOnceOps

final def asInstanceOf[T0]: T0

Cast the receiver object to be of type T0.

Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

returns: the receiver object.

Definition Classes: Any
Exceptions thrown: ClassCastException if the receiver object is not an instance of the erasure of type T0.

def buffered: BufferedIterator.this.type

Creates a buffered iterator from this iterator.

returns: a buffered iterator producing the same values as this iterator.

Definition Classes: BufferedIterator → Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.
See also: scala.collection.BufferedIterator

def clone(): AnyRef

Create a copy of the receiver object.

The default implementation of the clone method is platform dependent.

returns: a copy of the receiver object.

Attributes: protected[java.lang]
Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.CloneNotSupportedException]) @native()
Note: not specified by SLS as a member of AnyRef

def collect[B](pf: PartialFunction[A, B]): Iterator[B]

Builds a new iterator by applying a partial function to all elements of this iterator on which the function is defined.

B: the element type of the returned iterator.
pf: the partial function which filters and maps the iterator.
returns: a new iterator resulting from applying the given partial function pf to each element on which it is defined and collecting the results. The order of the elements is preserved.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def collectFirst[B](pf: PartialFunction[A, B]): Option[B]

Finds the first element of the collection for which the given partial function is defined, and applies the partial function to it.

Note: may not terminate for infinite-sized collections.

Note: might return different results for different runs, unless the underlying collection type is ordered.

pf: the partial function
returns: an option value containing pf applied to the first value for which it is defined, or None if none exists.

Definition Classes: IterableOnceOps

def concat[B >: A](xs: => IterableOnce[B]): Iterator[B]

Definition Classes: Iterator

def contains(elem: Any): Boolean

Tests whether this iterator contains a given value as an element.

Note: may not terminate for infinite iterators.

elem: the element to test.
returns: true if this iterator produces some value that is is equal (as determined by ==) to elem, false otherwise.

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

def copyToArray[B >: A](xs: Array[B], start: Int, len: Int): Int

Copy elements to an array, returning the number of elements written.

Fills the given array xs starting at index start with at most len elements of this collection.

Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached, or len elements have been copied.

B: the type of the elements of the array.
xs: the array to fill.
start: the starting index of xs.
len: the maximal number of elements to copy.
returns: the number of elements written to the array

Definition Classes: IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change. Note: will not terminate for infinite-sized collections.

def copyToArray[B >: A](xs: Array[B], start: Int): Int

Copy elements to an array, returning the number of elements written.

Fills the given array xs starting at index start with values of this collection.

Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached.

B: the type of the elements of the array.
xs: the array to fill.
start: the starting index of xs.
returns: the number of elements written to the array Note: will not terminate for infinite-sized collections.

Definition Classes: IterableOnceOps

def copyToArray[B >: A](xs: Array[B]): Int

Copy elements to an array, returning the number of elements written.

Fills the given array xs starting at index start with values of this collection.

Copying will stop once either all the elements of this collection have been copied, or the end of the array is reached.

B: the type of the elements of the array.
xs: the array to fill.
returns: the number of elements written to the array Note: will not terminate for infinite-sized collections.

Definition Classes: IterableOnceOps

def corresponds[B](that: IterableOnce[B])(p: (A, B) => Boolean): Boolean

Tests whether every element of this collection's iterator relates to the corresponding element of another collection by satisfying a test predicate.

B: the type of the elements of that
that: the other collection
p: the test predicate, which relates elements from both collections
returns: true if both collections have the same length and p(x, y) is true for all corresponding elements x of this iterator and y of that, otherwise false

Definition Classes: IterableOnceOps

def count(p: (A) => Boolean): Int

Counts the number of elements in the collection which satisfy a predicate.

p: the predicate used to test elements.
returns: the number of elements satisfying the predicate p.

Definition Classes: IterableOnceOps

def distinct: Iterator[A]

Builds a new iterator from this one without any duplicated elements on it.

returns: iterator with distinct elements

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

def distinctBy[B](f: (A) => B): Iterator[A]

Builds a new iterator from this one without any duplicated elements as determined by == after applying the transforming function f.

B: the type of the elements after being transformed by f
f: The transforming function whose result is used to determine the uniqueness of each element
returns: iterator with distinct elements

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

def drop(n: Int): Iterator[A]

Selects all elements except first n ones.

Note: might return different results for different runs, unless the underlying collection type is ordered.

n: the number of elements to drop from this iterator.
returns: a iterator consisting of all elements of this iterator except the first n ones, or else the empty iterator, if this iterator has less than n elements. If n is negative, don't drop any elements.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def dropWhile(p: (A) => Boolean): Iterator[A]

Drops longest prefix of elements that satisfy a predicate.

Note: might return different results for different runs, unless the underlying collection type is ordered.

p: The predicate used to test elements.
returns: the longest suffix of this iterator whose first element does not satisfy the predicate p.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def duplicate: (Iterator[A], Iterator[A])

Creates two new iterators that both iterate over the same elements as this iterator (in the same order). The duplicate iterators are considered equal if they are positioned at the same element.

Given that most methods on iterators will make the original iterator unfit for further use, this methods provides a reliable way of calling multiple such methods on an iterator.

returns: a pair of iterators

Definition Classes: Iterator
Note: The implementation may allocate temporary storage for elements iterated by one iterator but not yet by the other.
,
Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.

def ensuring(cond: (BufferedIterator[A]) => Boolean, msg: => Any): BufferedIterator[A]

Implicit: This member is added by an implicit conversion from BufferedIterator[A] toEnsuring[BufferedIterator[A]] performed by method Ensuring in scala.Predef.
Definition Classes: Ensuring

def ensuring(cond: (BufferedIterator[A]) => Boolean): BufferedIterator[A]

Implicit: This member is added by an implicit conversion from BufferedIterator[A] toEnsuring[BufferedIterator[A]] performed by method Ensuring in scala.Predef.
Definition Classes: Ensuring

def ensuring(cond: Boolean, msg: => Any): BufferedIterator[A]

Implicit: This member is added by an implicit conversion from BufferedIterator[A] toEnsuring[BufferedIterator[A]] performed by method Ensuring in scala.Predef.
Definition Classes: Ensuring

def ensuring(cond: Boolean): BufferedIterator[A]

Implicit: This member is added by an implicit conversion from BufferedIterator[A] toEnsuring[BufferedIterator[A]] performed by method Ensuring in scala.Predef.
Definition Classes: Ensuring

final def eq(arg0: AnyRef): Boolean

Tests whether the argument (that) is a reference to the receiver object (this).

The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:

x

y

AnyRef

x.eq(y)

true

false

x

AnyRef

x.eq(null)

null.eq(x)

false

null.eq(null)

true

When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

returns: true if the argument is a reference to the receiver object; false otherwise.

Definition Classes: AnyRef

def equals(arg0: AnyRef): Boolean

The equality method for reference types. Default implementation delegates to eq.

def exists(p: (A) => Boolean): Boolean

Tests whether a predicate holds for at least one element of this collection.

Note: may not terminate for infinite-sized collections.

p: the predicate used to test elements.
returns: true if the given predicate p is satisfied by at least one element of this collection, otherwise false

Definition Classes: IterableOnceOps

def filter(p: (A) => Boolean): Iterator[A]

Selects all elements of this iterator which satisfy a predicate.

p: the predicate used to test elements.
returns: a new iterator consisting of all elements of this iterator that satisfy the given predicate p. The order of the elements is preserved.

Definition Classes: Iterator → IterableOnceOps

def filterNot(p: (A) => Boolean): Iterator[A]

Selects all elements of this iterator which do not satisfy a predicate.

returns: a new iterator consisting of all elements of this iterator that do not satisfy the given predicate pred. Their order may not be preserved.

Definition Classes: Iterator → IterableOnceOps

def finalize(): Unit

Called by the garbage collector on the receiver object when there are no more references to the object.

The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

Attributes: protected[java.lang]
Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.Throwable])
Note: not specified by SLS as a member of AnyRef

def find(p: (A) => Boolean): Option[A]

Finds the first element of the collection satisfying a predicate, if any.

Note: may not terminate for infinite-sized collections.

Note: might return different results for different runs, unless the underlying collection type is ordered.

p: the predicate used to test elements.
returns: an option value containing the first element in the collection that satisfies p, or None if none exists.

Definition Classes: IterableOnceOps

def flatMap[B](f: (A) => IterableOnce[B]): Iterator[B]

Builds a new iterator by applying a function to all elements of this iterator and using the elements of the resulting collections.

For example:

def getWords(lines: Seq[String]): Seq[String] = lines flatMap (line => line split "\\W+")

The type of the resulting collection is guided by the static type of iterator. This might cause unexpected results sometimes. For example:

// lettersOf will return a Seq[Char] of likely repeated letters, instead of a Set
def lettersOf(words: Seq[String]) = words flatMap (word => word.toSet)

// lettersOf will return a Set[Char], not a Seq
def lettersOf(words: Seq[String]) = words.toSet flatMap ((word: String) => word.toSeq)

// xs will be an Iterable[Int]
val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2)

// ys will be a Map[Int, Int]
val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)

B: the element type of the returned collection.
f: the function to apply to each element.
returns: a new iterator resulting from applying the given collection-valued function f to each element of this iterator and concatenating the results.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def flatten[B](implicit ev: (A) => IterableOnce[B]): Iterator[B]

Converts this iterator of traversable collections into a iterator formed by the elements of these traversable collections.

The resulting collection's type will be guided by the type of iterator. For example:

val xs = List(
           Set(1, 2, 3),
           Set(1, 2, 3)
         ).flatten
// xs == List(1, 2, 3, 1, 2, 3)

val ys = Set(
           List(1, 2, 3),
           List(3, 2, 1)
         ).flatten
// ys == Set(1, 2, 3)

B: the type of the elements of each traversable collection.
returns: a new iterator resulting from concatenating all element iterators.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def fold[A1 >: A](z: A1)(op: (A1, A1) => A1): A1

Folds the elements of this collection using the specified associative binary operator. The default implementation in IterableOnce is equivalent to foldLeft but may be overridden for more efficient traversal orders.

The order in which operations are performed on elements is unspecified and may be nondeterministic.

Note: will not terminate for infinite-sized collections.

A1: a type parameter for the binary operator, a supertype of A.
z: a neutral element for the fold operation; may be added to the result an arbitrary number of times, and must not change the result (e.g., Nil for list concatenation, 0 for addition, or 1 for multiplication).
op: a binary operator that must be associative.
returns: the result of applying the fold operator op between all the elements and z, or z if this collection is empty.

Definition Classes: IterableOnceOps

def foldLeft[B](z: B)(op: (B, A) => B): B

Applies a binary operator to a start value and all elements of this collection, 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 or the operator is associative and commutative.

B

the result type of the binary operator.

z

the start value.

op

the binary operator.

returns

the result of inserting op between consecutive elements of this collection, going left to right with the start value z on the left:

op(...op(z, x_1), x_2, ..., x_n)

where x₁, ..., x_n are the elements of this collection. Returns z if this collection is empty.

Definition Classes: IterableOnceOps

def foldRight[B](z: B)(op: (A, B) => B): B

Applies a binary operator to all elements of this collection and a start value, going right to left.

Note: will not terminate for infinite-sized collections.

Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.

B

the result type of the binary operator.

z

the start value.

op

the binary operator.

returns

the result of inserting op between consecutive elements of this collection, going right to left with the start value z on the right:

op(x_1, op(x_2, ... op(x_n, z)...))

where x₁, ..., x_n are the elements of this collection. Returns z if this collection is empty.

Definition Classes: IterableOnceOps

def forall(p: (A) => Boolean): Boolean

Tests whether a predicate holds for all elements of this collection.

Note: may not terminate for infinite-sized collections.

p: the predicate used to test elements.
returns: true if this collection is empty or the given predicate p holds for all elements of this collection, otherwise false.

Definition Classes: IterableOnceOps

def foreach[U](f: (A) => U): Unit

Apply f to each element for its side effects Note: [U] parameter needed to help scalac's type inference.

Definition Classes: IterableOnceOps

def formatted(fmtstr: String): String

Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

Implicit: This member is added by an implicit conversion from BufferedIterator[A] toStringFormat[BufferedIterator[A]] performed by method StringFormat in scala.Predef.
Definition Classes: StringFormat
Annotations: @inline()

final def getClass(): Class[_ <: AnyRef]

Returns the runtime class representation of the object.

returns: a class object corresponding to the runtime type of the receiver.

Definition Classes: AnyRef → Any
Annotations: @native()

def grouped[B >: A](size: Int): GroupedIterator[B]

Returns an iterator which groups this iterator into fixed size blocks. Example usages:

// Returns List(List(1, 2, 3), List(4, 5, 6), List(7)))
(1 to 7).iterator.grouped(3).toList
// Returns List(List(1, 2, 3), List(4, 5, 6))
(1 to 7).iterator.grouped(3).withPartial(false).toList
// Returns List(List(1, 2, 3), List(4, 5, 6), List(7, 20, 25)
// Illustrating that withPadding's argument is by-name.
val it2 = Iterator.iterate(20)(_ + 5)
(1 to 7).iterator.grouped(3).withPadding(it2.next).toList

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def hashCode(): Int

The hashCode method for reference types. See hashCode in scala.Any.

returns: the hash code value for this object.

Definition Classes: AnyRef → Any
Annotations: @native()

def headOption: Option[A]

Returns an option of the next element of an iterator without advancing beyond it.

returns: the next element of this iterator if it has a next element None if it does not

def indexOf[B >: A](elem: B, from: Int): Int

Returns the index of the first occurrence of the specified object in this iterable object after or at some start index.

Note: may not terminate for infinite iterators.

elem: element to search for.
from: the start index
returns: the index >= from of the first occurrence of elem in the values produced by this iterator, or -1 if such an element does not exist until the end of the iterator is reached.

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

def indexOf[B >: A](elem: B): Int

Returns the index of the first occurrence of the specified object in this iterable object.

Note: may not terminate for infinite iterators.

elem: element to search for.
returns: the index of the first occurrence of elem in the values produced by this iterator, or -1 if such an element does not exist until the end of the iterator is reached.

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

def indexWhere(p: (A) => Boolean, from: Int = 0): Int

Definition Classes: Iterator

def isEmpty: Boolean

Tests whether the iterator is empty.

Note: Implementations in subclasses that are not repeatedly traversable must take care not to consume any elements when isEmpty is called.

returns: true if the iterator contains no elements, false otherwise.

Definition Classes: Iterator → IterableOnceOps
Annotations: @deprecatedOverriding("isEmpty is defined as !hasNext; override hasNext instead", "2.13.0")

final def isInstanceOf[T0]: Boolean

Test whether the dynamic type of the receiver object is T0.

Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

returns: true if the receiver object is an instance of erasure of type T0; false otherwise.

Definition Classes: Any

def isTraversableAgain: Boolean

Tests whether this collection can be repeatedly traversed. Always true for Iterables and false for Iterators unless overridden.

returns: true if it is repeatedly traversable, false otherwise.

Definition Classes: IterableOnceOps

final def iterator: Iterator[A]

Iterator can be used only once

Definition Classes: Iterator → IterableOnce
Annotations: @inline()

def knownSize: Int

returns: The number of elements in this collection, if it can be cheaply computed, -1 otherwise. Cheaply usually means: Not requiring a collection traversal.

Definition Classes: IterableOnce

final def length: Int

Definition Classes: Iterator
Annotations: @inline()

def map[B](f: (A) => B): Iterator[B]

Builds a new iterator by applying a function to all elements of this iterator.

B: the element type of the returned iterator.
f: the function to apply to each element.
returns: a new iterator resulting from applying the given function f to each element of this iterator and collecting the results.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def max[B >: A](implicit ord: math.Ordering[B]): A

Finds the largest element.

B: The type over which the ordering is defined.
ord: An ordering to be used for comparing elements.
returns: the largest element of this collection with respect to the ordering ord.

Definition Classes: IterableOnceOps
Exceptions thrown: UnsupportedOperationException if this collection is empty.

def maxBy[B](f: (A) => B)(implicit cmp: math.Ordering[B]): A

Finds the first element which yields the largest value measured by function f.

B: The result type of the function f.
f: The measuring function.
cmp: An ordering to be used for comparing elements.
returns: the first element of this collection with the largest value measured by function f with respect to the ordering cmp.

Definition Classes: IterableOnceOps
Exceptions thrown: UnsupportedOperationException if this collection is empty.

def maxByOption[B](f: (A) => B)(implicit cmp: math.Ordering[B]): Option[A]

Finds the first element which yields the largest value measured by function f.

B: The result type of the function f.
f: The measuring function.
cmp: An ordering to be used for comparing elements.
returns: an option value containing the first element of this collection with the largest value measured by function f with respect to the ordering cmp.

Definition Classes: IterableOnceOps

def maxOption[B >: A](implicit ord: math.Ordering[B]): Option[A]

Finds the largest element.

B: The type over which the ordering is defined.
ord: An ordering to be used for comparing elements.
returns: an option value containing the largest element of this collection with respect to the ordering ord.

Definition Classes: IterableOnceOps

def min[B >: A](implicit ord: math.Ordering[B]): A

Finds the smallest element.

B: The type over which the ordering is defined.
ord: An ordering to be used for comparing elements.
returns: the smallest element of this collection with respect to the ordering ord.

Definition Classes: IterableOnceOps
Exceptions thrown: UnsupportedOperationException if this collection is empty.

def minBy[B](f: (A) => B)(implicit cmp: math.Ordering[B]): A

Finds the first element which yields the smallest value measured by function f.

B: The result type of the function f.
f: The measuring function.
cmp: An ordering to be used for comparing elements.
returns: the first element of this collection with the smallest value measured by function f with respect to the ordering cmp.

Definition Classes: IterableOnceOps
Exceptions thrown: UnsupportedOperationException if this collection is empty.

def minByOption[B](f: (A) => B)(implicit cmp: math.Ordering[B]): Option[A]

Finds the first element which yields the smallest value measured by function f.

B: The result type of the function f.
f: The measuring function.
cmp: An ordering to be used for comparing elements.
returns: an option value containing the first element of this collection with the smallest value measured by function f with respect to the ordering cmp.

Definition Classes: IterableOnceOps

def minOption[B >: A](implicit ord: math.Ordering[B]): Option[A]

Finds the smallest element.

B: The type over which the ordering is defined.
ord: An ordering to be used for comparing elements.
returns: an option value containing the smallest element of this collection with respect to the ordering ord.

Definition Classes: IterableOnceOps

final def mkString: String

Displays all elements of this collection in a string.

Delegates to addString, which can be overridden.

returns: a string representation of this collection. In the resulting string the string representations (w.r.t. the method toString) of all elements of this collection follow each other without any separator string.

Definition Classes: IterableOnceOps
Annotations: @inline()

final def mkString(sep: String): String

Displays all elements of this collection in a string using a separator string.

Delegates to addString, which can be overridden.

sep: the separator string.
returns: a string representation of this collection. In the resulting string the string representations (w.r.t. the method toString) of all elements of this collection are separated by the string sep.

Definition Classes: IterableOnceOps
Annotations: @inline()

final def mkString(start: String, sep: String, end: String): String

Displays all elements of this collection in a string using start, end, and separator strings.

Delegates to addString, which can be overridden.

start: the starting string.
sep: the separator string.
end: the ending string.
returns: a string representation of this collection. The resulting string begins with the string start and ends with the string end. Inside, the string representations (w.r.t. the method toString) of all elements of this collection are separated by the string sep.

Definition Classes: IterableOnceOps

final def ne(arg0: AnyRef): Boolean

Equivalent to !(this eq that).

returns: true if the argument is not a reference to the receiver object; false otherwise.

Definition Classes: AnyRef

def nextOption(): Option[A]

Wraps the value of next() in an option.

returns: Some(next) if a next element exists, None otherwise.

Definition Classes: Iterator

def nonEmpty: Boolean

Tests whether the collection is not empty.

returns: true if the collection contains at least one element, false otherwise.

Definition Classes: IterableOnceOps
Annotations: @deprecatedOverriding("nonEmpty is defined as !isEmpty; override isEmpty instead", "2.13.0")

final def notify(): Unit

Wakes up a single thread that is waiting on the receiver object's monitor.

Definition Classes: AnyRef
Annotations: @native()
Note: not specified by SLS as a member of AnyRef

final def notifyAll(): Unit

Wakes up all threads that are waiting on the receiver object's monitor.

Definition Classes: AnyRef
Annotations: @native()
Note: not specified by SLS as a member of AnyRef

def padTo[B >: A](len: Int, elem: B): Iterator[B]

A copy of this iterator with an element value appended until a given target length is reached.

B: the element type of the returned iterator.
len: the target length
elem: the padding value
returns: a new iterator consisting of all elements of this iterator followed by the minimal number of occurrences of elem so that the resulting collection has a length of at least len.

Definition Classes: Iterator

def partition(p: (A) => Boolean): (Iterator[A], Iterator[A])

Partitions this iterator in two iterators according to a predicate.

p: the predicate on which to partition
returns: a pair of iterators: the iterator that satisfies the predicate p and the iterator that does not. The relative order of the elements in the resulting iterators is the same as in the original iterator.

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.

def patch[B >: A](from: Int, patchElems: Iterator[B], replaced: Int): Iterator[B]

Returns this iterator with patched values. Patching at negative indices is the same as patching starting at 0. Patching at indices at or larger than the length of the original iterator appends the patch to the end. If more values are replaced than actually exist, the excess is ignored.

from: The start index from which to patch
patchElems: The iterator of patch values
replaced: The number of values in the original iterator that are replaced by the patch.

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on, as well as the one passed as a parameter, and use only the iterator that was returned. Using the old iterators is undefined, subject to change, and may result in changes to the new iterator as well.

def product[B >: A](implicit num: math.Numeric[B]): B

Multiplies up the elements of this collection.

B: the result type of the * operator.
num: an implicit parameter defining a set of numeric operations which includes the * operator to be used in forming the product.
returns: the product of all elements of this collection with respect to the * operator in num.

Definition Classes: IterableOnceOps

def reduce[B >: A](op: (B, B) => B): B

Reduces the elements of this collection using the specified associative binary operator.

The order in which operations are performed on elements is unspecified and may be nondeterministic.

B: A type parameter for the binary operator, a supertype of A.
op: A binary operator that must be associative.
returns: The result of applying reduce operator op between all the elements if the collection is nonempty.

Definition Classes: IterableOnceOps
Exceptions thrown: UnsupportedOperationException if this collection is empty.

def reduceLeft[B >: A](op: (B, A) => B): B

Applies a binary operator to all elements of this collection, 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 or the operator is associative and commutative.

B

the result type of the binary operator.

op

the binary operator.

returns

the result of inserting op between consecutive elements of this collection, going left to right:

op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n)

where x₁, ..., x_n are the elements of this collection.

Definition Classes: IterableOnceOps
Exceptions thrown: UnsupportedOperationException if this collection is empty.

def reduceLeftOption[B >: A](op: (B, A) => B): Option[B]

Optionally applies a binary operator to all elements of this collection, 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 or the operator is associative and commutative.

B: the result type of the binary operator.
op: the binary operator.
returns: an option value containing the result of reduceLeft(op) if this collection is nonempty, None otherwise.

Definition Classes: IterableOnceOps

def reduceOption[B >: A](op: (B, B) => B): Option[B]

Reduces the elements of this collection, if any, using the specified associative binary operator.

The order in which operations are performed on elements is unspecified and may be nondeterministic.

B: A type parameter for the binary operator, a supertype of A.
op: A binary operator that must be associative.
returns: An option value containing result of applying reduce operator op between all the elements if the collection is nonempty, and None otherwise.

Definition Classes: IterableOnceOps

def reduceRight[B >: A](op: (A, B) => B): B

Applies a binary operator to all elements of this collection, going right to left.

Note: will not terminate for infinite-sized collections.

Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.

B

the result type of the binary operator.

op

the binary operator.

returns

the result of inserting op between consecutive elements of this collection, going right to left:

op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))

where x₁, ..., x_n are the elements of this collection.

Definition Classes: IterableOnceOps
Exceptions thrown: UnsupportedOperationException if this collection is empty.

def reduceRightOption[B >: A](op: (A, B) => B): Option[B]

Optionally applies a binary operator to all elements of this collection, going right to left.

Note: will not terminate for infinite-sized collections.

Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.

B: the result type of the binary operator.
op: the binary operator.
returns: an option value containing the result of reduceRight(op) if this collection is nonempty, None otherwise.

Definition Classes: IterableOnceOps

def reversed: Iterable[A]

Attributes: protected
Definition Classes: IterableOnceOps

def sameElements[B >: A](that: IterableOnce[B]): Boolean

Definition Classes: Iterator

def scanLeft[B](z: B)(op: (B, A) => B): Iterator[B]

Produces a iterator containing cumulative results of applying the operator going left to right, including the initial value.

Note: will not terminate for infinite-sized collections.

Note: might return different results for different runs, unless the underlying collection type is ordered.

B: the type of the elements in the resulting collection
z: the initial value
op: the binary operator applied to the intermediate result and the element
returns: collection with intermediate results

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def size: Int

The size of this collection.

Note: will not terminate for infinite-sized collections.

returns: the number of elements in this collection.

Definition Classes: IterableOnceOps

def slice(from: Int, until: Int): Iterator[A]

Selects an interval of elements. The returned iterator is made up of all elements x which satisfy the invariant:

from <= indexOf(x) < until

Note: might return different results for different runs, unless the underlying collection type is ordered.

from: the lowest index to include from this iterator.
until: the lowest index to EXCLUDE from this iterator.
returns: a iterator containing the elements greater than or equal to index from extending up to (but not including) index until of this iterator.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def sliceIterator(from: Int, until: Int): Iterator[A]

Creates an optionally bounded slice, unbounded if until is negative.

Attributes: protected
Definition Classes: Iterator

def sliding[B >: A](size: Int, step: Int = 1): GroupedIterator[B]

Returns an iterator which presents a "sliding window" view of this iterator. The first argument is the window size, and the second argument step is how far to advance the window on each iteration. The step defaults to 1.

The default GroupedIterator can be configured to either pad a partial result to size size or suppress the partial result entirely.

Example usages:

// Returns List(List(1, 2, 3), List(2, 3, 4), List(3, 4, 5))
(1 to 5).iterator.sliding(3).toList
// Returns List(List(1, 2, 3, 4), List(4, 5))
(1 to 5).iterator.sliding(4, 3).toList
// Returns List(List(1, 2, 3, 4))
(1 to 5).iterator.sliding(4, 3).withPartial(false).toList
// Returns List(List(1, 2, 3, 4), List(4, 5, 20, 25))
// Illustrating that withPadding's argument is by-name.
val it2 = Iterator.iterate(20)(_ + 5)
(1 to 5).iterator.sliding(4, 3).withPadding(it2.next).toList

returns: An iterator producing Seq[B]s of size size, except the last element (which may be the only element) will be truncated if there are fewer than size elements remaining to be grouped. This behavior can be configured.

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def span(p: (A) => Boolean): (Iterator[A], Iterator[A])

Splits this iterator into a prefix/suffix pair according to a predicate.

Note: c span p is equivalent to (but possibly more efficient than) (c takeWhile p, c dropWhile p), provided the evaluation of the predicate p does not cause any side-effects.

Note: might return different results for different runs, unless the underlying collection type is ordered.

p: the test predicate
returns: a pair consisting of the longest prefix of this iterator whose elements all satisfy p, and the rest of this iterator.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.

def splitAt(n: Int): (Iterator[A], Iterator[A])

Splits this collection into a prefix/suffix pair at a given position.

Note: c splitAt n is equivalent to (but possibly more efficient than) (c take n, c drop n).

Note: might return different results for different runs, unless the underlying collection type is ordered.

n: the position at which to split.
returns: a pair of collections consisting of the first n elements of this collection, and the other elements.

Definition Classes: IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.

def stepper[S <: Stepper[_]](implicit shape: StepperShape[A, S]): S

Returns a Stepper for the elements of this collection.

The Stepper enables creating a Java stream to operate on the collection, see scala.jdk.StreamConverters. For collections holding primitive values, the Stepper can be used as an iterator which doesn't box the elements.

The implicit StepperShape parameter defines the resulting Stepper type according to the element type of this collection.

Int

Short

Byte

Char

IntStepper

Double

Float

DoubleStepper

Long

LongStepper

AnyStepper

Note that this method is overridden in subclasses and the return type is refined to S with EfficientSplit, for example IndexedSeqOps.stepper. For Steppers marked with scala.collection.Stepper.EfficientSplit, the converters in scala.jdk.StreamConverters allow creating parallel streams, whereas bare Steppers can be converted only to sequential streams.

Definition Classes: IterableOnce

def sum[B >: A](implicit num: math.Numeric[B]): B

Sums up the elements of this collection.

B: the result type of the + operator.
num: an implicit parameter defining a set of numeric operations which includes the + operator to be used in forming the sum.
returns: the sum of all elements of this collection with respect to the + operator in num.

Definition Classes: IterableOnceOps

final def synchronized[T0](arg0: => T0): T0

Definition Classes: AnyRef

def take(n: Int): Iterator[A]

Selects the first n elements.

Note: might return different results for different runs, unless the underlying collection type is ordered.

n: the number of elements to take from this iterator.
returns: a iterator consisting only of the first n elements of this iterator, or else the whole iterator, if it has less than n elements. If n is negative, returns an empty iterator.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def takeWhile(p: (A) => Boolean): Iterator[A]

Takes longest prefix of elements that satisfy a predicate.

Note: might return different results for different runs, unless the underlying collection type is ordered.

p: The predicate used to test elements.
returns: the longest prefix of this iterator whose elements all satisfy the predicate p.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def tapEach[U](f: (A) => U): Iterator[A]

Applies a side-effecting function to each element in this collection. Strict collections will apply f to their elements immediately, while lazy collections like Views and LazyLists will only apply f on each element if and when that element is evaluated, and each time that element is evaluated.

U: the return type of f
f: a function to apply to each element in this iterator
returns: The same logical collection as this

Definition Classes: Iterator → IterableOnceOps

def to[C1](factory: Factory[A, C1]): C1

Given a collection factory factory, convert this collection to the appropriate representation for the current element type A. Example uses:

xs.to(List) xs.to(ArrayBuffer) xs.to(BitSet) // for xs: Iterable[Int]

Definition Classes: IterableOnceOps

def toArray[B >: A](implicit arg0: ClassTag[B]): Array[B]

Convert collection to array.

Definition Classes: IterableOnceOps

final def toBuffer[B >: A]: Buffer[B]

Definition Classes: IterableOnceOps
Annotations: @inline()

def toIndexedSeq: immutable.IndexedSeq[A]

Definition Classes: IterableOnceOps

def toList: immutable.List[A]

Definition Classes: IterableOnceOps

def toMap[K, V](implicit ev: <:<[A, (K, V)]): immutable.Map[K, V]

Definition Classes: IterableOnceOps

def toSeq: immutable.Seq[A]

returns: This collection as a Seq[A]. This is equivalent to to(Seq) but might be faster.

Definition Classes: IterableOnceOps

def toSet[B >: A]: immutable.Set[B]

Definition Classes: IterableOnceOps

def toString(): String

Converts this iterator to a string.

returns: "<iterator>"

Definition Classes: Iterator → AnyRef → Any
Note: Reuse: The iterator remains valid for further use whatever result is returned.

def toVector: immutable.Vector[A]

Definition Classes: IterableOnceOps

final def wait(): Unit

Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.InterruptedException])

final def wait(arg0: Long, arg1: Int): Unit

Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.InterruptedException])

final def wait(arg0: Long): Unit

Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.InterruptedException]) @native()

def withFilter(p: (A) => Boolean): Iterator[A]

Creates an iterator over all the elements of this iterator that satisfy the predicate p. The order of the elements is preserved.

Note: withFilter is the same as filter on iterators. It exists so that for-expressions with filters work over iterators.

p: the predicate used to test values.
returns: an iterator which produces those values of this iterator which satisfy the predicate p.

Definition Classes: Iterator
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

def zip[B](that: IterableOnce[B]): Iterator[(A, B)]

Definition Classes: Iterator

def zipAll[A1 >: A, B](that: IterableOnce[B], thisElem: A1, thatElem: B): Iterator[(A1, B)]

Definition Classes: Iterator

def zipWithIndex: Iterator[(A, Int)]

Zips this iterator with its indices.

returns: A new iterator containing pairs consisting of all elements of this iterator paired with their index. Indices start at 0.

Definition Classes: Iterator → IterableOnceOps
Note: Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.13.0/scala/collection/BufferedIterator.html