IterableOnceOps
This implementation trait can be mixed into an IterableOnce
to get the basic methods that are shared between Iterator
and Iterable
. The IterableOnce
must support multiple calls to iterator
but may or may not return the same Iterator
every time.
Attributes
- Source
- IterableOnce.scala
- Graph
-
- Supertypes
-
class Any
- Known subtypes
-
trait Iterable[A]class IntMap[T]class LongMap[T]trait Seq[A]class AbstractSeq[A]class ArraySeq[A]class ofBooleanclass ofByteclass ofCharclass ofDoubleclass ofFloatclass ofIntclass ofLongclass ofRef[T]class ofShortclass ofUnitclass LazyList[A]class List[A]class ::[A]object Nilclass NumericRange[T]class Exclusive[T]class Inclusive[T]class Queue[A]class Rangeclass Exclusiveclass Inclusiveclass Stream[A]class Cons[A]object Emptyclass Vector[A]class WrappedStringtrait IndexedSeq[A]trait LinearSeq[A]trait Set[A]class AbstractSet[A]class BitSetclass BitSet1class BitSet2class BitSetNclass HashSet[A]class ListSet[A]class Set1[A]class Set2[A]class Set3[A]class Set4[A]class ImmutableKeySortedSetclass TreeSet[A]class ValueSettrait SortedSet[A]trait Iterable[A]class AbstractIterable[A]class PriorityQueue[A]class LongMap[V]class SystemPropertiestrait Seq[A]class AbstractSeq[A]class AbstractBuffer[A]class ArrayBuffer[A]class ArrayDeque[A]class Queue[A]class Stack[A]class ListBuffer[A]class UnrolledBuffer[T]class ArraySeq[T]class ofBooleanclass ofByteclass ofCharclass ofDoubleclass ofFloatclass ofIntclass ofLongclass ofRef[T]class ofShortclass ofUnitclass StringBuildertrait Buffer[A]trait IndexedBuffer[A]trait IndexedSeq[T]class AnyAccumulator[A]class DoubleAccumulatorclass IntAccumulatorclass LongAccumulatortrait Set[A]class AbstractSet[A]class BitSetclass HashSet[A]class LinkedHashSet[A]class TreeSet[A]trait SortedSet[A]trait Iterable[A]class AbstractIterable[A]class AbstractSeq[A]class AbstractSet[A]class AbstractView[A]class AbstractSeqView[A]class AbstractIndexedSeqView[A]class ArrayBufferView[A]class Slice[A]class StringViewclass Id[A]class Id[A]class Reverse[A]class Reverse[A]class Appended[A]class Appended[A]class Appended[A]class Concat[A]class Concat[A]class Concat[A]class Drop[A]class Drop[A]class Drop[A]class DropRight[A]class DropRight[A]class DropRight[A]class DropWhile[A]class Elems[A]object Emptyclass Fill[A]class Filter[A]class Iterate[A]class PadTo[A]class Prepended[A]class Prepended[A]class Prepended[A]class Single[A]class Tabulate[A]class Take[A]class Take[A]class Take[A]class TakeRight[A]class TakeRight[A]class TakeRight[A]class TakeWhile[A]class Updated[A]class ZipWithIndex[A]trait Seq[A]trait IndexedSeq[A]trait LinearSeq[A]trait Set[A]trait SortedSet[A]trait BitSettrait View[A]trait SeqView[A]trait IndexedSeqView[A]trait BitSetOps[C]trait Iterator[A]class AbstractIterator[A]class GroupedIterator[B]class BufferedLineIteratorclass LineIteratorclass MatchIteratortrait BufferedIterator[A]class Sourceclass BufferedSourceShow all
- Self type
-
IterableOnce[A]
Members list
Value members
Abstract methods
Builds a new collection by applying a partial function to all elements of this collection on which the function is defined.
Builds a new collection by applying a partial function to all elements of this collection on which the function is defined.
Type parameters
- B
-
the element type of the returned collection.
Value parameters
- pf
-
the partial function which filters and maps the collection.
Attributes
- Returns
-
a new collection 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. - Source
- IterableOnce.scala
Selects all elements except first n ones.
Selects all elements except first n ones.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Value parameters
- n
-
the number of elements to drop from this collection.
Attributes
- Returns
-
a collection consisting of all elements of this collection except the first
n
ones, or else the empty collection, if this collection has less thann
elements. Ifn
is negative, don't drop any elements. - Source
- IterableOnce.scala
Drops longest prefix of elements that satisfy a predicate.
Drops longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Value parameters
- p
-
The predicate used to test elements.
Attributes
- Returns
-
the longest suffix of this collection whose first element does not satisfy the predicate
p
. - Source
- IterableOnce.scala
Selects all elements of this collection which satisfy a predicate.
Selects all elements of this collection which satisfy a predicate.
Value parameters
- p
-
the predicate used to test elements.
Attributes
- Returns
-
a new collection consisting of all elements of this collection that satisfy the given predicate
p
. The order of the elements is preserved. - Source
- IterableOnce.scala
Selects all elements of this collection which do not satisfy a predicate.
Selects all elements of this collection which do not satisfy a predicate.
Value parameters
- pred
-
the predicate used to test elements.
Attributes
- Returns
-
a new collection consisting of all elements of this collection that do not satisfy the given predicate
pred
. Their order may not be preserved. - Source
- IterableOnce.scala
Builds a new collection by applying a function to all elements of this collection and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this collection 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 collection. 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)
Type parameters
- B
-
the element type of the returned collection.
Value parameters
- f
-
the function to apply to each element.
Attributes
- Returns
-
a new collection resulting from applying the given collection-valued function
f
to each element of this collection and concatenating the results. - Source
- IterableOnce.scala
Converts this collection of iterable collections into a collection formed by the elements of these iterable collections.
Converts this collection of iterable collections into a collection formed by the elements of these iterable collections.
The resulting collection's type will be guided by the type of collection. 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)
Type parameters
- B
-
the type of the elements of each iterable collection.
Value parameters
- asIterable
-
an implicit conversion which asserts that the element type of this collection is an
Iterable
.
Attributes
- Returns
-
a new collection resulting from concatenating all element collections.
- Source
- IterableOnce.scala
Builds a new collection by applying a function to all elements of this collection.
Builds a new collection by applying a function to all elements of this collection.
Type parameters
- B
-
the element type of the returned collection.
Value parameters
- f
-
the function to apply to each element.
Attributes
- Returns
-
a new collection resulting from applying the given function
f
to each element of this collection and collecting the results. - Source
- IterableOnce.scala
Produces a collection containing cumulative results of applying the operator going left to right, including the initial value.
Produces a collection 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.
Type parameters
- B
-
the type of the elements in the resulting collection
Value parameters
- op
-
the binary operator applied to the intermediate result and the element
- z
-
the initial value
Attributes
- Returns
-
collection with intermediate results
- Source
- IterableOnce.scala
Selects an interval of elements.
Selects an interval of elements. The returned collection 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.
Value parameters
- from
-
the lowest index to include from this collection.
- until
-
the lowest index to EXCLUDE from this collection.
Attributes
- Returns
-
a collection containing the elements greater than or equal to index
from
extending up to (but not including) indexuntil
of this collection. - Source
- IterableOnce.scala
Splits this collection into a prefix/suffix pair according to a predicate.
Splits this collection 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.
Value parameters
- p
-
the test predicate
Attributes
- Returns
-
a pair consisting of the longest prefix of this collection whose elements all satisfy
p
, and the rest of this collection. - Source
- IterableOnce.scala
Selects the first n elements.
Selects the first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Value parameters
- n
-
the number of elements to take from this collection.
Attributes
- Returns
-
a collection consisting only of the first
n
elements of this collection, or else the whole collection, if it has less thann
elements. Ifn
is negative, returns an empty collection. - Source
- IterableOnce.scala
Takes longest prefix of elements that satisfy a predicate.
Takes longest prefix of elements that satisfy a predicate.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Value parameters
- p
-
The predicate used to test elements.
Attributes
- Returns
-
the longest prefix of this collection whose elements all satisfy the predicate
p
. - Source
- IterableOnce.scala
Applies a side-effecting function to each element in this collection.
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.
Type parameters
- U
-
the return type of f
Value parameters
- f
-
a function to apply to each element in this collection
Attributes
- Returns
-
The same logical collection as this
- Source
- IterableOnce.scala
Zips this collection with its indices.
Zips this collection with its indices.
Attributes
- Returns
-
A new collection containing pairs consisting of all elements of this collection paired with their index. Indices start at
0
. - Example
-
List("a", "b", "c").zipWithIndex == List(("a", 0), ("b", 1), ("c", 2))
- Source
- IterableOnce.scala
Concrete methods
Appends all elements of this collection to a string builder using start, end, and separator strings.
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)
Value parameters
- b
-
the string builder to which elements are appended.
- end
-
the ending string.
- sep
-
the separator string.
- start
-
the starting string.
Attributes
- Returns
-
the string builder
b
to which elements were appended. - Source
- IterableOnce.scala
Appends all elements of this collection to a string builder using a separator string.
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
Value parameters
- b
-
the string builder to which elements are appended.
- sep
-
the separator string.
Attributes
- Returns
-
the string builder
b
to which elements were appended. - Source
- IterableOnce.scala
Appends all elements of this collection to a string builder.
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
Value parameters
- b
-
the string builder to which elements are appended.
Attributes
- Returns
-
the string builder
b
to which elements were appended. - Source
- IterableOnce.scala
Finds the first element of the collection for which the given partial function is defined, and applies the partial function to it.
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.
Value parameters
- pf
-
the partial function
Attributes
- Returns
-
an option value containing pf applied to the first value for which it is defined, or
None
if none exists. - Example
-
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
- Source
- IterableOnce.scala
Copy elements to an array, returning the number of elements written.
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.
Type parameters
- B
-
the type of the elements of the array.
Value parameters
- xs
-
the array to fill.
Attributes
- Returns
-
the number of elements written to the array
- Note
-
Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.
- Source
- IterableOnce.scala
Copy elements to an array, returning the number of elements written.
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.
Type parameters
- B
-
the type of the elements of the array.
Value parameters
- start
-
the starting index of xs.
- xs
-
the array to fill.
Attributes
- Returns
-
the number of elements written to the array
- Note
-
Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.
- Source
- IterableOnce.scala
Copy elements to an array, returning the number of elements written.
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.
Type parameters
- B
-
the type of the elements of the array.
Value parameters
- len
-
the maximal number of elements to copy.
- start
-
the starting index of xs.
- xs
-
the array to fill.
Attributes
- Returns
-
the number of elements written to the array
- Note
-
Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.
- Source
- IterableOnce.scala
Tests whether every element of this collection's iterator relates to the corresponding element of another collection by satisfying a test predicate.
Tests whether every element of this collection's iterator relates to the corresponding element of another collection by satisfying a test predicate.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
the type of the elements of
that
Value parameters
- p
-
the test predicate, which relates elements from both collections
- that
-
the other collection
Attributes
- Returns
-
true
if both collections have the same length andp(x, y)
istrue
for all corresponding elementsx
of this iterator andy
ofthat
, otherwisefalse
- Source
- IterableOnce.scala
Counts the number of elements in the collection which satisfy a predicate.
Counts the number of elements in the collection which satisfy a predicate.
Note: will not terminate for infinite-sized collections.
Value parameters
- p
-
the predicate used to test elements.
Attributes
- Returns
-
the number of elements satisfying the predicate
p
. - Source
- IterableOnce.scala
Tests whether a predicate holds for at least one element of this collection.
Tests whether a predicate holds for at least one element of this collection.
Note: may not terminate for infinite-sized collections.
Value parameters
- p
-
the predicate used to test elements.
Attributes
- Returns
-
true
if the given predicatep
is satisfied by at least one element of this collection, otherwisefalse
- Source
- IterableOnce.scala
Finds the first element of the collection satisfying a predicate, if any.
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.
Value parameters
- p
-
the predicate used to test elements.
Attributes
- Returns
-
an option value containing the first element in the collection that satisfies
p
, orNone
if none exists. - Source
- IterableOnce.scala
Folds the elements of this collection using the specified associative binary operator.
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.
Type parameters
- A1
-
a type parameter for the binary operator, a supertype of
A
.
Value parameters
- op
-
a binary operator that must be associative.
- 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).
Attributes
- Returns
-
the result of applying the fold operator
op
between all the elements andz
, orz
if this collection is empty. - Source
- IterableOnce.scala
Applies a binary operator to a start value and all elements of this collection, going left to right.
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.
Type parameters
- B
-
the result type of the binary operator.
Value parameters
- op
-
the binary operator.
- z
-
the start value.
Attributes
- Returns
-
the result of inserting
op
between consecutive elements of this collection, going left to right with the start valuez
on the left:op(...op(z, x1), x2, ..., xn)
wherex1, ..., xn
are the elements of this collection. Returnsz
if this collection is empty. - Source
- IterableOnce.scala
Applies a binary operator to all elements of this collection and a start value, going right to left.
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.
Type parameters
- B
-
the result type of the binary operator.
Value parameters
- op
-
the binary operator.
- z
-
the start value.
Attributes
- Returns
-
the result of inserting
op
between consecutive elements of this collection, going right to left with the start valuez
on the right:op(x1, op(x2, ... op(xn, z)...))
wherex1, ..., xn
are the elements of this collection. Returnsz
if this collection is empty. - Source
- IterableOnce.scala
Tests whether a predicate holds for all elements of this collection.
Tests whether a predicate holds for all elements of this collection.
Note: may not terminate for infinite-sized collections.
Value parameters
- p
-
the predicate used to test elements.
Attributes
- Returns
-
true
if this collection is empty or the given predicatep
holds for all elements of this collection, otherwisefalse
. - Source
- IterableOnce.scala
Apply f
to each element for its side effects Note: [U] parameter needed to help scalac's type inference.
Apply f
to each element for its side effects Note: [U] parameter needed to help scalac's type inference.
Attributes
- Source
- IterableOnce.scala
Tests whether the collection is empty.
Tests whether the collection is empty.
Note: The default implementation creates and discards an iterator.
Note: Implementations in subclasses that are not repeatedly iterable must take care not to consume any elements when isEmpty
is called.
Attributes
- Returns
-
true
if the collection contains no elements,false
otherwise. - Source
- IterableOnce.scala
Tests whether this collection can be repeatedly traversed.
Tests whether this collection can be repeatedly traversed. Always true for Iterables and false for Iterators unless overridden.
Attributes
- Returns
-
true
if it is repeatedly traversable,false
otherwise. - Source
- IterableOnce.scala
Finds the largest element.
Finds the largest element.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The type over which the ordering is defined.
Value parameters
- ord
-
An ordering to be used for comparing elements.
Attributes
- Returns
-
the largest element of this collection with respect to the ordering
ord
. - Throws
-
UnsupportedOperationException if this collection is empty.
- Source
- IterableOnce.scala
Finds the first element which yields the largest value measured by function f.
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the function f.
Value parameters
- cmp
-
An ordering to be used for comparing elements.
- f
-
The measuring function.
Attributes
- Returns
-
the first element of this collection with the largest value measured by function f with respect to the ordering
cmp
. - Throws
-
UnsupportedOperationException if this collection is empty.
- Source
- IterableOnce.scala
Finds the first element which yields the largest value measured by function f.
Finds the first element which yields the largest value measured by function f.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the function f.
Value parameters
- cmp
-
An ordering to be used for comparing elements.
- f
-
The measuring function.
Attributes
- 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
. - Source
- IterableOnce.scala
Finds the largest element.
Finds the largest element.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The type over which the ordering is defined.
Value parameters
- ord
-
An ordering to be used for comparing elements.
Attributes
- Returns
-
an option value containing the largest element of this collection with respect to the ordering
ord
. - Source
- IterableOnce.scala
Finds the smallest element.
Finds the smallest element.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The type over which the ordering is defined.
Value parameters
- ord
-
An ordering to be used for comparing elements.
Attributes
- Returns
-
the smallest element of this collection with respect to the ordering
ord
. - Throws
-
UnsupportedOperationException if this collection is empty.
- Source
- IterableOnce.scala
Finds the first element which yields the smallest value measured by function f.
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the function f.
Value parameters
- cmp
-
An ordering to be used for comparing elements.
- f
-
The measuring function.
Attributes
- Returns
-
the first element of this collection with the smallest value measured by function f with respect to the ordering
cmp
. - Throws
-
UnsupportedOperationException if this collection is empty.
- Source
- IterableOnce.scala
Finds the first element which yields the smallest value measured by function f.
Finds the first element which yields the smallest value measured by function f.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the function f.
Value parameters
- cmp
-
An ordering to be used for comparing elements.
- f
-
The measuring function.
Attributes
- 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
. - Source
- IterableOnce.scala
Finds the smallest element.
Finds the smallest element.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The type over which the ordering is defined.
Value parameters
- ord
-
An ordering to be used for comparing elements.
Attributes
- Returns
-
an option value containing the smallest element of this collection with respect to the ordering
ord
. - Source
- IterableOnce.scala
Displays all elements of this collection in a string using start, end, and separator strings.
Displays all elements of this collection in a string using start, end, and separator strings.
Delegates to addString, which can be overridden.
Value parameters
- end
-
the ending string.
- sep
-
the separator string.
- start
-
the starting string.
Attributes
- Returns
-
a string representation of this collection. The resulting string begins with the string
start
and ends with the stringend
. Inside, the string representations (w.r.t. the methodtoString
) of all elements of this collection are separated by the stringsep
. - Example
-
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
- Source
- IterableOnce.scala
Displays all elements of this collection in a string using a separator string.
Displays all elements of this collection in a string using a separator string.
Delegates to addString, which can be overridden.
Value parameters
- sep
-
the separator string.
Attributes
- 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 stringsep
. - Example
-
List(1, 2, 3).mkString("|") = "1|2|3"
- Source
- IterableOnce.scala
Displays all elements of this collection in a string.
Displays all elements of this collection in a string.
Delegates to addString, which can be overridden.
Attributes
- 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. - Source
- IterableOnce.scala
Tests whether the collection is not empty.
Tests whether the collection is not empty.
Attributes
- Returns
-
true
if the collection contains at least one element,false
otherwise. - Source
- IterableOnce.scala
Multiplies together the elements of this collection.
Multiplies together the elements of this collection.
The default implementation uses reduce
for a known non-empty collection, foldLeft
otherwise.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
the result type of the
*
operator.
Value parameters
- num
-
an implicit parameter defining a set of numeric operations which includes the
*
operator to be used in forming the product.
Attributes
- Returns
-
the product of all elements of this collection with respect to the
*
operator innum
. - Source
- IterableOnce.scala
Reduces the elements of this collection using the specified associative binary operator.
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.
Type parameters
- B
-
A type parameter for the binary operator, a supertype of
A
.
Value parameters
- op
-
A binary operator that must be associative.
Attributes
- Returns
-
The result of applying reduce operator
op
between all the elements if the collection is nonempty. - Throws
-
UnsupportedOperationException if this collection is empty.
- Source
- IterableOnce.scala
Applies a binary operator to all elements of this collection, going left to right.
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.
Type parameters
- B
-
the result type of the binary operator.
Value parameters
- op
-
the binary operator.
Attributes
- Returns
-
the result of inserting
op
between consecutive elements of this collection, going left to right:op( op( ... op(x1, x2) ..., xn-1), xn)
wherex1, ..., xn
are the elements of this collection. - Throws
-
UnsupportedOperationException if this collection is empty.
- Source
- IterableOnce.scala
Optionally applies a binary operator to all elements of this collection, going left to right.
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.
Type parameters
- B
-
the result type of the binary operator.
Value parameters
- op
-
the binary operator.
Attributes
- Returns
-
an option value containing the result of
reduceLeft(op)
if this collection is nonempty,None
otherwise. - Source
- IterableOnce.scala
Reduces the elements of this collection, if any, using the specified associative binary operator.
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.
Type parameters
- B
-
A type parameter for the binary operator, a supertype of
A
.
Value parameters
- op
-
A binary operator that must be associative.
Attributes
- Returns
-
An option value containing result of applying reduce operator
op
between all the elements if the collection is nonempty, andNone
otherwise. - Source
- IterableOnce.scala
Applies a binary operator to all elements of this collection, going right to left.
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.
Type parameters
- B
-
the result type of the binary operator.
Value parameters
- op
-
the binary operator.
Attributes
- Returns
-
the result of inserting
op
between consecutive elements of this collection, going right to left:op(x1, op(x2, ..., op(xn-1, xn)...))
wherex1, ..., xn
are the elements of this collection. - Throws
-
UnsupportedOperationException if this collection is empty.
- Source
- IterableOnce.scala
Optionally applies a binary operator to all elements of this collection, going right to left.
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.
Type parameters
- B
-
the result type of the binary operator.
Value parameters
- op
-
the binary operator.
Attributes
- Returns
-
an option value containing the result of
reduceRight(op)
if this collection is nonempty,None
otherwise. - Source
- IterableOnce.scala
Attributes
- Source
- IterableOnce.scala
The size of this collection.
The size of this collection.
Note: will not terminate for infinite-sized collections.
Attributes
- Returns
-
the number of elements in this collection.
- Source
- IterableOnce.scala
Splits this collection into a prefix/suffix pair at a given position.
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.
Value parameters
- n
-
the position at which to split.
Attributes
- Returns
-
a pair of collections consisting of the first
n
elements of this collection, and the other elements. - Source
- IterableOnce.scala
Sums the elements of this collection.
Sums the elements of this collection.
The default implementation uses reduce
for a known non-empty collection, foldLeft
otherwise.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
the result type of the
+
operator.
Value parameters
- num
-
an implicit parameter defining a set of numeric operations which includes the
+
operator to be used in forming the sum.
Attributes
- Returns
-
the sum of all elements of this collection with respect to the
+
operator innum
. - Source
- IterableOnce.scala
Given a collection factory factory
, convert this collection to the appropriate representation for the current element type A
.
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]
Attributes
- Source
- IterableOnce.scala
Convert collection to array.
Convert collection to array.
Implementation note: DO NOT call Array.from from this method.
Attributes
- Source
- IterableOnce.scala
Attributes
- Source
- IterableOnce.scala
Attributes
- Source
- IterableOnce.scala
Attributes
- Source
- IterableOnce.scala
Attributes
- Source
- IterableOnce.scala
Attributes
- Returns
-
This collection as a
Seq[A]
. This is equivalent toto(Seq)
but might be faster. - Source
- IterableOnce.scala
Attributes
- Source
- IterableOnce.scala
Attributes
- Source
- IterableOnce.scala
Deprecated methods
Attributes
- Deprecated
- true
- Source
- IterableOnce.scala
Attributes
- Deprecated
- true
- Source
- IterableOnce.scala
Attributes
- Deprecated
- true
- Source
- IterableOnce.scala
Attributes
- Deprecated
- true
- Source
- IterableOnce.scala
Tests whether this collection is known to have a finite size.
Tests whether this collection is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as Stream
, the predicate returns true
if all elements have been computed. It returns false
if the stream is not yet evaluated to the end. Non-empty Iterators usually return false
even if they were created from a collection with a known finite size.
Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that hasDefiniteSize
returns true
. However, checking hasDefiniteSize
can provide an assurance that size is well-defined and non-termination is not a concern.
Attributes
- Returns
-
true
if this collection is known to have finite size,false
otherwise. - See also
-
method
knownSize
for a more useful alternative - Deprecated
-
This method is deprecated in 2.13 because it does not provide any actionable information. As noted above, even the collection library itself does not use it. When there is no guarantee that a collection is finite, it is generally best to attempt a computation anyway and document that it will not terminate for infinite collections rather than backing out because this would prevent performing the computation on collections that are in fact finite even though
hasDefiniteSize
returnsfalse
. - Source
- IterableOnce.scala
Attributes
- Deprecated
- true
- Source
- IterableOnce.scala
Attributes
- Deprecated
- true
- Source
- IterableOnce.scala