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 LazyListIterable[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 TreeSet[A]trait 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 MatchIteratortrait BufferedIterator[A]class Sourceclass BufferedSourceShow all
- Self type
-
Members list
Value members
Abstract methods
Builds a new $ccoll by applying a partial function to all elements of this $coll on which the function is defined.
Builds a new $ccoll by applying a partial function to all elements of this $coll on which the function is defined.
Type parameters
- B
-
the element type of the returned $coll.
Value parameters
- pf
-
the partial function which filters and maps the $coll.
Attributes
- Returns
-
a new $ccoll 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 the first n
ones.
Selects all elements except the 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 $coll.
Attributes
- Returns
-
a $coll consisting of all elements of this $coll except the first
n
ones, or else the empty $coll, if this $coll has less thann
elements. Ifn
is negative, don't drop any elements. - Source
- IterableOnce.scala
Selects all elements except the longest prefix that satisfies a predicate.
Selects all elements except the longest prefix that satisfies a predicate.
The matching prefix starts with the first element of this $coll, and the element following the prefix is the first element that does not satisfy the predicate. The matching prefix may be empty, so that this method returns the entire $coll.
Example:
scala> List(1, 2, 3, 100, 4).dropWhile(n => n < 10)
val res0: List[Int] = List(100, 4)
scala> List(1, 2, 3, 100, 4).dropWhile(n => n == 0)
val res1: List[Int] = List(1, 2, 3, 100, 4)
Use span to obtain both the prefix and suffix. Use filterNot to drop all elements that satisfy the 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 $coll whose first element does not satisfy the predicate
p
. - Source
- IterableOnce.scala
Selects all elements of this $coll which satisfy a predicate.
Selects all elements of this $coll which satisfy a predicate.
Value parameters
- p
-
the predicate used to test elements.
Attributes
- Returns
-
a new $coll consisting of all elements of this $coll that satisfy the given predicate
p
. The order of the elements is preserved. - Source
- IterableOnce.scala
Selects all elements of this $coll which do not satisfy a predicate.
Selects all elements of this $coll which do not satisfy a predicate.
Value parameters
- pred
-
the predicate used to test elements.
Attributes
- Returns
-
a new $coll consisting of all elements of this $coll that do not satisfy the given predicate
pred
. Their order may not be preserved. - Source
- IterableOnce.scala
Builds a new $ccoll by applying a function to all elements of this $coll and using the elements of the resulting collections.
Builds a new $ccoll by applying a function to all elements of this $coll 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 this $coll. 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 => 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 $ccoll resulting from applying the given collection-valued function
f
to each element of this $coll and concatenating the results. - Source
- IterableOnce.scala
Given that the elements of this collection are themselves iterable collections, converts this $coll into a $ccoll comprising the elements of these iterable collections.
Given that the elements of this collection are themselves iterable collections, converts this $coll into a $ccoll comprising the elements of these iterable collections.
The resulting collection's type will be guided by the type of $coll. 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 $coll is an
Iterable
.
Attributes
- Returns
-
a new $ccoll resulting from concatenating all element collections.
- Source
- IterableOnce.scala
Builds a new $ccoll by applying a function to all elements of this $coll.
Builds a new $ccoll by applying a function to all elements of this $coll.
Type parameters
- B
-
the element type of the returned $ccoll.
Value parameters
- f
-
the function to apply to each element.
Attributes
- Returns
-
a new $ccoll resulting from applying the given function
f
to each element of this $coll and collecting the results. - Source
- IterableOnce.scala
Produces a $coll containing cumulative results of applying the operator going left to right, including the initial value.
Produces a $coll 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 $coll 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 $coll.
- until
-
the lowest index to EXCLUDE from this $coll.
Attributes
- Returns
-
a $coll containing the elements greater than or equal to index
from
extending up to (but not including) indexuntil
of this $coll. - Source
- IterableOnce.scala
Splits this $coll into a prefix/suffix pair according to a predicate.
Splits this $coll 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 $coll whose elements all satisfy
p
, and the rest of this $coll. - 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 $coll.
Attributes
- Returns
-
a $coll consisting only of the first
n
elements of this $coll, or else the whole $coll, if it has less thann
elements. Ifn
is negative, returns an empty $coll. - Source
- IterableOnce.scala
Selects the longest prefix of elements that satisfy a predicate.
Selects the longest prefix of elements that satisfy a predicate.
The matching prefix starts with the first element of this $coll, and the element following the prefix is the first element that does not satisfy the predicate. The matching prefix may empty, so that this method returns an empty $coll.
Example:
scala> List(1, 2, 3, 100, 4).takeWhile(n => n < 10)
val res0: List[Int] = List(1, 2, 3)
scala> List(1, 2, 3, 100, 4).takeWhile(n => n == 0)
val res1: List[Int] = List()
Use span to obtain both the prefix and suffix. Use filter to retain only those elements from the entire $coll that satisfy the 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 $coll 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 $coll
Attributes
- Returns
-
The same logical collection as this
- Source
- IterableOnce.scala
Zips this $coll with its indices.
Zips this $coll with its indices.
Attributes
- Returns
-
A new $ccoll containing pairs consisting of all elements of this $coll 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 $coll to a string builder using start, end, and separator strings.
Appends all elements of this $coll 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 $coll 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 $coll to a string builder using a separator string.
Appends all elements of this $coll 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 $coll, 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 $coll to a string builder.
Appends all elements of this $coll to a string builder. The written text consists of the string representations (w.r.t. the method toString
) of all elements of this $coll 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 $coll for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the $coll 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
Copies elements to an array, returning the number of elements written.
Copies elements to an array, returning the number of elements written.
Fills the given array xs
starting at index start
with values of this $coll.
Copying will stop once either all the elements of this $coll 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
Copies elements to an array, returning the number of elements written.
Copies elements to an array, returning the number of elements written.
Fills the given array xs
starting at index start
with values of this $coll.
Copying will stop once either all the elements of this $coll 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 $coll.
Copying will stop once either all the elements of this $coll 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 $coll which satisfy a predicate.
Counts the number of elements in the $coll 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 $coll.
Tests whether a predicate holds for at least one element of this $coll.
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 $coll, otherwisefalse
- Source
- IterableOnce.scala
Finds the first element of the $coll satisfying a predicate, if any.
Finds the first element of the $coll 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 $coll that satisfies
p
, orNone
if none exists. - Source
- IterableOnce.scala
Applies the given binary operator op
to the given initial value z
and all elements of this $coll.
Applies the given binary operator op
to the given initial value z
and all elements of this $coll.
For each application of the operator, each operand is either an element of this $coll, the initial value, or another such application of the operator.
The order of applications of the operator is unspecified and may be nondeterministic. Each element appears exactly once in the computation. The initial value may be used an arbitrary number of times, but at least once.
If this collection is ordered, then for any application of the operator, the element(s) appearing in the left operand will precede those in the right.
Note: might return different results for different runs, unless either of the following conditions is met: (1) the operator is associative, and the underlying collection type is ordered; or (2) the operator is associative and commutative. In either case, it is also necessary that the initial value be a neutral value for the operator, e.g. Nil
for List
concatenation or 1
for multiplication.
The default implementation in IterableOnce
is equivalent to foldLeft
but may be overridden for more efficient traversal orders.
Note: will not terminate for infinite-sized collections.
Type parameters
- A1
-
The type parameter for the binary operator, a supertype of
A
.
Value parameters
- op
-
A binary operator; must be associative for the result to always be the same across runs.
- z
-
An initial value; may be used an arbitrary number of times in the computation of the result; must be a neutral value for
op
for the result to always be the same across runs.
Attributes
- Returns
-
The result of applying
op
between all the elements andz
, orz
if this $coll is empty. - Source
- IterableOnce.scala
Applies the given binary operator op
to the given initial value z
and all elements of this $coll, going left to right.
Applies the given binary operator op
to the given initial value z
and all elements of this $coll, going left to right. Returns the initial value if this $coll is empty.
"Going left to right" only makes sense if this collection is ordered: then if x1
, x2
, ..., xn
are the elements of this $coll, the result is op( op( ... op( op(z, x1), x2) ... ), xn)
.
If this collection is not ordered, then for each application of the operator, each right operand is an element. In addition, the leftmost operand is the initial value, and each other left operand is itself an application of the operator. The elements of this $coll and the initial value all appear exactly once in the computation.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the binary operator.
Value parameters
- op
-
A binary operator.
- z
-
An initial value.
Attributes
- Returns
-
The result of applying
op
toz
and all elements of this $coll, going left to right. Returnsz
if this $coll is empty. - Source
- IterableOnce.scala
Applies the given binary operator op
to all elements of this $coll and the given initial value z
, going right to left.
Applies the given binary operator op
to all elements of this $coll and the given initial value z
, going right to left. Returns the initial value if this $coll is empty.
"Going right to left" only makes sense if this collection is ordered: then if x1
, x2
, ..., xn
are the elements of this $coll, the result is op(x1, op(x2, op( ... op(xn, z) ... )))
.
If this collection is not ordered, then for each application of the operator, each left operand is an element. In addition, the rightmost operand is the initial value, and each other right operand is itself an application of the operator. The elements of this $coll and the initial value all appear exactly once in the computation.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the binary operator.
Value parameters
- op
-
A binary operator.
- z
-
An initial value.
Attributes
- Returns
-
The result of applying
op
to all elements of this $coll andz
, going right to left. Returnsz
if this $coll is empty. - Source
- IterableOnce.scala
Tests whether a predicate holds for all elements of this $coll.
Tests whether a predicate holds for all elements of this $coll.
Note: may not terminate for infinite-sized collections.
Value parameters
- p
-
the predicate used to test elements.
Attributes
- Returns
-
true
if this $coll is empty or the given predicatep
holds for all elements of this $coll, otherwisefalse
. - Source
- IterableOnce.scala
Applies f
to each element for its side effects.
Applies 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 $coll is empty.
Tests whether the $coll 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 $coll contains no elements,false
otherwise. - Source
- IterableOnce.scala
Tests whether this $coll can be repeatedly traversed.
Tests whether this $coll 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 $coll with respect to the ordering
ord
. - Throws
-
UnsupportedOperationException if this $coll 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 $coll with the largest value measured by function
f
with respect to the orderingcmp
. - Throws
-
UnsupportedOperationException if this $coll 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 $coll with the largest value measured by function
f
with respect to the orderingcmp
. - 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 $coll 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 $coll with respect to the ordering
ord
. - Throws
-
UnsupportedOperationException if this $coll 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 $coll with the smallest value measured by function
f
with respect to the orderingcmp
. - Throws
-
UnsupportedOperationException if this $coll 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 $coll with the smallest value measured by function
f
with respect to the orderingcmp
. - 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 $coll with respect to the ordering
ord
. - Source
- IterableOnce.scala
Displays all elements of this $coll in a string using start, end, and separator strings.
Displays all elements of this $coll 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 $coll. 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 $coll are separated by the stringsep
. - Example
-
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
- Source
- IterableOnce.scala
Displays all elements of this $coll in a string using a separator string.
Displays all elements of this $coll 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 $coll. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this $coll are separated by the stringsep
. - Example
-
List(1, 2, 3).mkString("|") = "1|2|3"
- Source
- IterableOnce.scala
Displays all elements of this $coll in a string.
Displays all elements of this $coll in a string.
Delegates to addString, which can be overridden.
Attributes
- Returns
-
a string representation of this $coll. In the resulting string the string representations (w.r.t. the method
toString
) of all elements of this $coll follow each other without any separator string. - Source
- IterableOnce.scala
Tests whether the $coll is not empty.
Tests whether the $coll is not empty.
Attributes
- Returns
-
true
if the $coll 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 $coll with respect to the
*
operator innum
. - Source
- IterableOnce.scala
Applies the given binary operator op
to all elements of this $coll.
Applies the given binary operator op
to all elements of this $coll.
For each application of the operator, each operand is either an element of this $coll or another such application of the operator. The order of applications of the operator is unspecified and may be nondeterministic. Each element appears exactly once in the computation.
If this collection is ordered, then for any application of the operator, the element(s) appearing in the left operand will precede those in the right.
Note: might return different results for different runs, unless either of the following conditions is met: (1) the operator is associative, and the underlying collection type is ordered; or (2) the operator is associative and commutative.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The type parameter for the binary operator, a supertype of
A
.
Value parameters
- op
-
A binary operator; must be associative for the result to always be the same across runs.
Attributes
- Returns
-
The result of applying
op
between all the elements if the $coll is nonempty. - Throws
-
UnsupportedOperationException if this $coll is empty.
- Source
- IterableOnce.scala
Applies the given binary operator op
to all elements of this $coll, going left to right.
Applies the given binary operator op
to all elements of this $coll, going left to right.
"Going left to right" only makes sense if this collection is ordered: then if x1
, x2
, ..., xn
are the elements of this $coll, the result is op( op( op( ... op(x1, x2) ... ), xn-1), xn)
.
If this collection is not ordered, then for each application of the operator, each right operand is an element. In addition, the leftmost operand is the first element of this $coll and each other left operand is itself an application of the operator. Each element appears exactly once in the computation.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the binary operator, a supertype of
A
.
Value parameters
- op
-
A binary operator.
Attributes
- Returns
-
The result of applying
op
to all elements of this $coll, going left to right. - Throws
-
UnsupportedOperationException if this $coll is empty.
- Source
- IterableOnce.scala
If this $coll is nonempty, reduces it with the given binary operator op
, going left to right.
If this $coll is nonempty, reduces it with the given binary operator op
, going left to right.
The behavior is the same as reduceLeft except that the value is None
if the $coll is empty. Each element appears exactly once in the computation.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the binary operator, a supertype of
A
.
Value parameters
- op
-
A binary operator.
Attributes
- Returns
-
The result of reducing this $coll with
op
going left to right if the $coll is nonempty, inside aSome
, andNone
otherwise. - Source
- IterableOnce.scala
If this $coll is nonempty, reduces it with the given binary operator op
.
If this $coll is nonempty, reduces it with the given binary operator op
.
The behavior is the same as reduce except that the value is None
if the $coll is empty. The order of applications of the operator is unspecified and may be nondeterministic. Each element appears exactly once in the computation.
Note: might return different results for different runs, unless either of the following conditions is met: (1) the operator is associative, and the underlying collection type is ordered; or (2) the operator is associative and commutative.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
A type parameter for the binary operator, a supertype of
A
.
Value parameters
- op
-
A binary operator; must be associative for the result to always be the same across runs.
Attributes
- Returns
-
The result of reducing this $coll with
op
if the $coll is nonempty, inside aSome
, andNone
otherwise. - Source
- IterableOnce.scala
Applies the given binary operator op
to all elements of this $coll, going right to left.
Applies the given binary operator op
to all elements of this $coll, going right to left.
"Going right to left" only makes sense if this collection is ordered: then if x1
, x2
, ..., xn
are the elements of this $coll, the result is op(x1, op(x2, op( ... op(xn-1, xn) ... )))
.
If this collection is not ordered, then for each application of the operator, each left operand is an element. In addition, the rightmost operand is the last element of this $coll and each other right operand is itself an application of the operator. Each element appears exactly once in the computation.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the binary operator, a supertype of
A
.
Value parameters
- op
-
A binary operator.
Attributes
- Returns
-
The result of applying
op
to all elements of this $coll, going right to left. - Throws
-
UnsupportedOperationException if this $coll is empty.
- Source
- IterableOnce.scala
If this $coll is nonempty, reduces it with the given binary operator op
, going right to left.
If this $coll is nonempty, reduces it with the given binary operator op
, going right to left.
The behavior is the same as reduceRight except that the value is None
if the $coll is empty. Each element appears exactly once in the computation.
Note: might return different results for different runs, unless the underlying collection type is ordered or the operator is associative and commutative.
Note: will not terminate for infinite-sized collections.
Type parameters
- B
-
The result type of the binary operator, a supertype of
A
.
Value parameters
- op
-
A binary operator.
Attributes
- Returns
-
The result of reducing this $coll with
op
going right to left if the $coll is nonempty, inside aSome
, andNone
otherwise. - Source
- IterableOnce.scala
Attributes
- Source
- IterableOnce.scala
The size of this $coll.
The size of this $coll.
Note: will not terminate for infinite-sized collections.
Attributes
- Returns
-
the number of elements in this $coll.
- Source
- IterableOnce.scala
Splits this $coll into a prefix/suffix pair at a given position.
Splits this $coll 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 ${coll}s consisting of the first
n
elements of this $coll, 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 $coll with respect to the
+
operator innum
. - Source
- IterableOnce.scala
Given a collection factory factory
, converts this $coll to the appropriate representation for the current element type A
.
Given a collection factory factory
, converts this $coll 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
Converts this $coll to an Array
.
Converts this $coll to an Array
.
Implementation note: DO NOT call Array.from from this method.
Type parameters
- B
-
The type of elements of the result, a supertype of
A
.
Attributes
- Returns
-
This $coll as an
Array[B]
. - Source
- IterableOnce.scala
Converts this $coll to a Buffer
.
Converts this $coll to a Buffer
.
Type parameters
- B
-
The type of elements of the result, a supertype of
A
.
Attributes
- Returns
-
This $coll as a
Buffer[B]
. - Source
- IterableOnce.scala
Converts this $coll to an IndexedSeq
.
Converts this $coll to an IndexedSeq
.
Attributes
- Returns
-
This $coll as an
IndexedSeq[A]
. - Source
- IterableOnce.scala
Converts this $coll to a List
.
Converts this $coll to a List
.
Attributes
- Returns
-
This $coll as a
List[A]
. - Source
- IterableOnce.scala
Converts this $coll to a Map
, given an implicit coercion from the $coll's type to a key-value tuple.
Converts this $coll to a Map
, given an implicit coercion from the $coll's type to a key-value tuple.
Type parameters
- K
-
The key type for the resulting map.
- V
-
The value type for the resulting map.
Value parameters
- ev
-
An implicit coercion from
A
to[K, V]
.
Attributes
- Returns
-
This $coll as a
Map[K, V]
. - Source
- IterableOnce.scala
Attributes
- Returns
-
This $coll as a
Seq[A]
. This is equivalent toto(Seq)
but might be faster. - Source
- IterableOnce.scala
Converts this $coll to a Set
.
Converts this $coll to a Set
.
Type parameters
- B
-
The type of elements of the result, a supertype of
A
.
Attributes
- Returns
-
This $coll as a
Set[B]
. - Source
- IterableOnce.scala
Converts this $coll to a Vector
.
Converts this $coll to a Vector
.
Attributes
- Returns
-
This $coll as a
Vector[A]
. - Source
- IterableOnce.scala
Deprecated methods
Attributes
- Deprecated
-
[Since version 2.13.0]
Use foldLeft instead of /: - Source
- IterableOnce.scala
Attributes
- Deprecated
-
[Since version 2.13.0]
Use foldRight instead of :\\ - Source
- IterableOnce.scala
Aggregates the results of applying an operator to subsequent elements.
Aggregates the results of applying an operator to subsequent elements.
Since this method degenerates to foldLeft
for sequential (non-parallel) collections, where the combining operation is ignored, it is advisable to prefer foldLeft
for that case.
For parallel collections, use the aggregate
method specified by scala.collection.parallel.ParIterableLike
.
Type parameters
- B
-
the result type, produced by
seqop
,combop
, and by this function as a final result.
Value parameters
- combop
-
an associative operator for combining sequential results, unused for sequential collections.
- seqop
-
the binary operator used to accumulate the result.
- z
-
the start value, a neutral element for
seqop
.
Attributes
- Deprecated
-
[Since version 2.13.0]
For sequential collections, prefer `foldLeft(z)(seqop)`. For parallel collections, use `ParIterableLike#aggregate`. - Source
- IterableOnce.scala
Attributes
- Deprecated
-
[Since version 2.13.0]
Use `dest ++= coll` instead - Source
- IterableOnce.scala
Tests whether this $coll is known to have a finite size.
Tests whether this $coll 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
-
[Since version 2.13.0]
Check .knownSize instead of .hasDefiniteSize for more actionable information (see scaladoc for details)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
-
[Since version 2.13.0]
Use .iterator instead of .toIterator - Source
- IterableOnce.scala
Attributes
- Deprecated
-
[Since version 2.13.0]
Use .to(LazyList) instead of .toStream - Source
- IterableOnce.scala