A class supporting filtered operations.
A class supporting filtered operations. Instances of this class are
returned by method withFilter
.
Creates a new collection containing both the elements of this collection and the provided traversable object.
Creates a new collection containing both the elements of this collection and the provided traversable object.
the traversable object.
a new collection consisting of all the elements of this collection and xs
.
(Changed in version 2.8.0) ++
creates a new buffer. Use ++=
to add an element from this buffer and return that buffer itself.
[use case] Returns a new buffer proxy containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new buffer proxy containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the buffer proxy is the most specific superclass encompassing the element types of the two operands.
Example:
scala> val a = List(1) a: List[Int] = List(1) scala> val b = List(2) b: List[Int] = List(2) scala> val c = a ++ b c: List[Int] = List(1, 2) scala> val d = List('a') d: List[Char] = List(a) scala> val e = c ++ d e: List[AnyVal] = List(1, 2, a)
the element type of the returned collection.
the traversable to append.
a new buffer proxy which contains all elements of this buffer proxy
followed by all elements of that
.
As with ++
, returns a new collection containing the elements from the
left operand followed by the elements from the right operand.
As with ++
, returns a new collection containing the elements from the
left operand followed by the elements from the right operand.
It differs from ++
in that the right operand determines the type of
the resulting collection rather than the left one.
Mnemonic: the COLon is on the side of the new COLlection type.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
This overload exists because: for the implementation of ++:
we should
reuse that of ++
because many collections override it with more
efficient versions.
Since TraversableOnce
has no ++
method, we have to implement that
directly, but Traversable
and down can use the overload.
the element type of the returned collection.
the class of the returned collection. Where possible, That
is
the same class as the current collection class Repr
, but this
depends on the element type B
being admissible for that class,
which means that an implicit instance of type CanBuildFrom[Repr, B, That]
is found.
the traversable to append.
an implicit value of class CanBuildFrom
which determines
the result class That
from the current representation type Repr
and
and the new element type B
.
a new collection of type That
which contains all elements
of this traversable collection followed by all elements of that
.
[use case] As with ++
, returns a new collection containing the elements from the left operand followed by the
elements from the right operand.
As with ++
, returns a new collection containing the elements from the left operand followed by the
elements from the right operand.
It differs from ++
in that the right operand determines the type of
the resulting collection rather than the left one.
Mnemonic: the COLon is on the side of the new COLlection type.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
the element type of the returned collection.
the traversable to append.
a new buffer proxy which contains all elements of this buffer proxy
followed by all elements of that
.
Appends a number of elements provided by a traversable object.
Appends a number of elements provided by a traversable object.
the traversable object.
a reference to this buffer proxy.
Prepends elements to this buffer.
Prepends elements to this buffer.
the TraversableOnce containing the elements to prepend.
the buffer itself.
[use case] A copy of the buffer proxy with an element prepended.
A copy of the buffer proxy with an element prepended.
Note that :-ending operators are right associative (see example).
A mnemonic for +:
vs. :+
is: the COLon goes on the COLlection side.
Also, the original buffer proxy is not modified, so you will want to capture the result.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = 2 +: x y: List[Int] = List(2, 1) scala> println(x) List(1)
the prepended element
a new buffer proxy consisting of elem
followed
by all elements of this buffer proxy.
Append a single element to this buffer.
Append a single element to this buffer.
the element to append.
the buffer proxy itself
adds two or more elements to this growable collection.
adds two or more elements to this growable collection.
the first element to add.
the second element to add.
the remaining elements to add.
the growable collection itself
Prepend a single element to this buffer and return the identity of the buffer.
Prepend a single element to this buffer and return the identity of the buffer.
the element to append.
a reference to this buffer proxy.
Creates a new collection with all the elements of this collection except the two or more specified elements.
Creates a new collection with all the elements of this collection except the two or more specified elements.
the first element to remove.
the second element to remove.
the remaining elements to remove.
a new collection consisting of all the elements of this collection except
elem1
, elem2
and those in elems
.
(Changed in version 2.8.0) -
creates a new buffer. Use -=
to remove an element from this buffer and return that buffer itself.
Creates a new collection with all the elements of this collection except elem
.
Creates a new collection with all the elements of this collection except elem
.
the element to remove.
a new collection consisting of all the elements of this collection except elem
.
(Changed in version 2.8.0) -
creates a new buffer. Use -=
to remove an element from this buffer and return that buffer itself.
Creates a new collection with all the elements of this collection except those provided by the specified traversable object.
Creates a new collection with all the elements of this collection except those provided by the specified traversable object.
the traversable object.
a new collection with all the elements of this collection except
those in xs
(Changed in version 2.8.0) --
creates a new buffer. Use --=
to remove an element from this buffer and return that buffer itself.
Removes all elements produced by an iterator from this shrinkable collection.
Removes all elements produced by an iterator from this shrinkable collection.
the iterator producing the elements to remove.
the shrinkable collection itself
Removes a single element from this buffer, at its first occurrence.
Removes a single element from this buffer, at its first occurrence. If the buffer does not contain that element, it is unchanged.
the element to remove.
the buffer itself
Removes two or more elements from this shrinkable collection.
Removes two or more elements from this shrinkable collection.
the first element to remove.
the second element to remove.
the remaining elements to remove.
the shrinkable collection itself
Applies a binary operator to a start value and all elements of this traversable or iterator, going left to right.
Applies a binary operator to a start value and all elements of this traversable or iterator, going left to right.
Note: /:
is alternate syntax for foldLeft
; z /: xs
is the same as
xs foldLeft z
.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = (5 /: a)(_+_) b: Int = 15 scala> val c = (5 /: a)((x,y) => x + y) c: Int = 15
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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op
between consecutive elements of this traversable or iterator,
going left to right with the start value z
on the left:
op(...op(op(z, x_1), x_2), ..., x_n)
where x1, ..., xn
are the elements of this traversable or iterator.
[use case] A copy of this buffer proxy with an element appended.
A copy of this buffer proxy with an element appended.
A mnemonic for +:
vs. :+
is: the COLon goes on the COLlection side.
Example:
scala> val a = List(1) a: List[Int] = List(1) scala> val b = a :+ 2 b: List[Int] = List(1, 2) scala> println(a) List(1)
the appended element
a new buffer proxy consisting of
all elements of this buffer proxy followed by elem
.
Applies a binary operator to all elements of this traversable or iterator and a start value, going right to left.
Applies a binary operator to all elements of this traversable or iterator and a start value, going right to left.
Note: :\
is alternate syntax for foldRight
; xs :\ z
is the same as
xs foldRight z
.
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.
Examples:
Note that the folding function used to compute b is equivalent to that used to compute c.
scala> val a = List(1,2,3,4) a: List[Int] = List(1, 2, 3, 4) scala> val b = (a :\ 5)(_+_) b: Int = 15 scala> val c = (a :\ 5)((x,y) => x + y) c: Int = 15
the result type of the binary operator.
the start value
the binary operator
the result of inserting op
between consecutive elements of this traversable or iterator,
going right to left with the start value z
on the right:
op(x_1, op(x_2, ... op(x_n, z)...))
where x1, ..., xn
are the elements of this traversable or iterator.
Appends all elements of this traversable or iterator to a string builder.
Appends all elements of this traversable or iterator to a string builder.
The written text consists of the string representations (w.r.t. the method
toString
) of all elements of this traversable or iterator 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
the string builder to which elements are appended.
the string builder b
to which elements were appended.
Appends all elements of this traversable or iterator to a string builder using a separator string.
Appends all elements of this traversable or iterator 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 traversable or iterator, 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
the string builder to which elements are appended.
the separator string.
the string builder b
to which elements were appended.
Appends all elements of this traversable or iterator to a string builder using start, end, and separator strings.
Appends all elements of this traversable or iterator 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 traversable or iterator 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)
the string builder to which elements are appended.
the starting string.
the separator string.
the ending string.
the string builder b
to which elements were appended.
Aggregates the results of applying an operator to subsequent elements.
Aggregates the results of applying an operator to subsequent elements.
This is a more general form of fold
and reduce
. It is similar to
foldLeft
in that it doesn't require the result to be a supertype of the
element type. In addition, it allows parallel collections to be processed
in chunks, and then combines the intermediate results.
aggregate
splits the traversable or iterator into partitions and processes each
partition by sequentially applying seqop
, starting with z
(like
foldLeft
). Those intermediate results are then combined by using
combop
(like fold
). The implementation of this operation may operate
on an arbitrary number of collection partitions (even 1), so combop
may
be invoked an arbitrary number of times (even 0).
As an example, consider summing up the integer values of a list of chars.
The initial value for the sum is 0. First, seqop
transforms each input
character to an Int and adds it to the sum (of the partition). Then,
combop
just needs to sum up the intermediate results of the partitions:
List('a', 'b', 'c').aggregate(0)({ (sum, ch) => sum + ch.toInt }, { (p1, p2) => p1 + p2 })
the type of accumulated results
the initial value for the accumulated result of the partition - this
will typically be the neutral element for the seqop
operator (e.g.
Nil
for list concatenation or 0
for summation) and may be evaluated
more than once
an operator used to accumulate results within a partition
an associative operator used to combine results from different partitions
Composes this partial function with a transformation function that gets applied to results of this partial function.
Composes this partial function with a transformation function that gets applied to results of this partial function.
the result type of the transformation function.
the transformation function
a partial function with the same domain as this partial function, which maps
arguments x
to k(this(x))
.
Appends a sequence of elements to this buffer.
Appends a sequence of elements to this buffer.
the elements to append.
Appends a number of elements provided by a traversable object.
Appends a number of elements provided by a traversable object.
the traversable object.
Selects an element by its index in the buffer proxy.
Selects an element by its index in the buffer proxy.
Example:
scala> val x = List(1, 2, 3, 4, 5) x: List[Int] = List(1, 2, 3, 4, 5) scala> x(3) res1: Int = 4
the element of this buffer proxy at index idx
, where 0
indicates the first element.
IndexOutOfBoundsException
if idx
does not satisfy 0 <= idx < length
.
Applies this partial function to the given argument when it is contained in the function domain.
Applies this partial function to the given argument when it is contained in the function domain. Applies fallback function where this partial function is not defined.
Note that expression pf.applyOrElse(x, default)
is equivalent to
if(pf isDefinedAt x) pf(x) else default(x)
except that applyOrElse
method can be implemented more efficiently.
For all partial function literals the compiler generates an applyOrElse
implementation which
avoids double evaluation of pattern matchers and guards.
This makes applyOrElse
the basis for the efficient implementation for many operations and scenarios, such as:
orElse
/andThen
chains does not lead to
excessive apply
/isDefinedAt
evaluationlift
and unlift
do not evaluate source functions twice on each invocationrunWith
allows efficient imperative-style combining of partial functions
with conditionally applied actions For non-literal partial function classes with nontrivial isDefinedAt
method
it is recommended to override applyOrElse
with custom implementation that avoids
double isDefinedAt
evaluation. This may result in better performance
and more predictable behavior w.r.t. side effects.
the function argument
the fallback function
the result of this function or fallback function application.
2.10
Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.
Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.
The object with which this iterable collection should be compared
true
, if this iterable collection can possibly equal that
, false
otherwise. The test
takes into consideration only the run-time types of objects but ignores their elements.
Clears the buffer contents.
Clears the buffer contents.
Return a clone of this buffer.
Return a clone of this buffer.
a Buffer
with the same elements.
[use case] Builds a new collection by applying a partial function to all elements of this buffer proxy on which the function is defined.
Builds a new collection by applying a partial function to all elements of this buffer proxy on which the function is defined.
the element type of the returned collection.
the partial function which filters and maps the buffer proxy.
a new buffer proxy 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.
Finds the first element of the traversable or iterator for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the traversable or iterator 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.
the partial function
an option value containing pf applied to the first
value for which it is defined, or None
if none exists.
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
Iterates over combinations.
Iterates over combinations. A _combination_ of length n
is a subsequence of
the original sequence, with the elements taken in order. Thus, "xy"
and "yy"
are both length-2 combinations of "xyy"
, but "yx"
is not. If there is
more than one way to generate the same subsequence, only one will be returned.
For example, "xyyy"
has three different ways to generate "xy"
depending on
whether the first, second, or third "y"
is selected. However, since all are
identical, only one will be chosen. Which of the three will be taken is an
implementation detail that is not defined.
An Iterator which traverses the possible n-element combinations of this sequence.
"abbbc".combinations(2) = Iterator(ab, ac, bb, bc)
The factory companion object that builds instances of class Buffer
.
The factory companion object that builds instances of class Buffer
.
(or its Iterable
superclass where class Buffer
is not a Seq
.)
Composes two instances of Function1 in a new Function1, with this function applied last.
Composes two instances of Function1 in a new Function1, with this function applied last.
the type to which function g
can be applied
a function A => T1
a new function f
such that f(x) == apply(g(x))
Tests whether this sequence contains a given value as an element.
Tests whether this sequence contains a given value as an element.
Note: may not terminate for infinite-sized collections.
the element to test.
true
if this sequence has an element that is equal (as
determined by ==
) to elem
, false
otherwise.
Tests whether this sequence contains a given sequence as a slice.
Tests whether this sequence contains a given sequence as a slice.
Note: may not terminate for infinite-sized collections.
the sequence to test
true
if this sequence contains a slice with the same elements
as that
, otherwise false
.
[use case] Copies the elements of this buffer proxy to an array.
Copies the elements of this buffer proxy to an array.
Fills the given array xs
with at most len
elements of
this buffer proxy, starting at position start
.
Copying will stop once either the end of the current buffer proxy is reached,
or the end of the target array is reached, or len
elements have been copied.
the array to fill.
the starting index.
the maximal number of elements to copy.
[use case] Copies the elements of this buffer proxy to an array.
Copies the elements of this buffer proxy to an array.
Fills the given array xs
with values of this buffer proxy.
Copying will stop once either the end of the current buffer proxy is reached,
or the end of the target array is reached.
the array to fill.
[use case] Copies the elements of this buffer proxy to an array.
Copies the elements of this buffer proxy to an array.
Fills the given array xs
with values of this buffer proxy, beginning at index start
.
Copying will stop once either the end of the current buffer proxy is reached,
or the end of the target array is reached.
the array to fill.
the starting index.
Copies all elements of this traversable or iterator to a buffer.
Copies all elements of this traversable or iterator to a buffer.
Note: will not terminate for infinite-sized collections.
The buffer to which elements are copied.
Tests whether every element of this sequence relates to the corresponding element of another sequence by satisfying a test predicate.
Tests whether every element of this sequence relates to the corresponding element of another sequence by satisfying a test predicate.
the type of the elements of that
the other sequence
the test predicate, which relates elements from both sequences
true
if both sequences have the same length and
p(x, y)
is true
for all corresponding elements x
of this sequence
and y
of that
, otherwise false
.
Counts the number of elements in the traversable or iterator which satisfy a predicate.
Counts the number of elements in the traversable or iterator which satisfy a predicate.
the predicate used to test elements.
the number of elements satisfying the predicate p
.
[use case] Computes the multiset difference between this buffer proxy and another sequence.
Computes the multiset difference between this buffer proxy and another sequence.
the sequence of elements to remove
a new buffer proxy which contains all elements of this buffer proxy
except some of occurrences of elements that also appear in that
.
If an element value x
appears
n times in that
, then the first n occurrences of x
will not form
part of the result, but any following occurrences will.
Builds a new sequence from this sequence without any duplicate elements.
Builds a new sequence from this sequence without any duplicate elements.
Note: will not terminate for infinite-sized collections.
A new sequence which contains the first occurrence of every element of this sequence.
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.
the number of elements to drop from this iterable collection.
a iterable collection consisting of all elements of this iterable collection except the first n
ones, or else the
empty iterable collection, if this iterable collection has less than n
elements.
Selects all elements except last n ones.
Selects all elements except last n ones.
Note: might return different results for different runs, unless the underlying collection type is ordered.
The number of elements to take
a iterable collection consisting of all elements of this iterable collection except the last n
ones, or else the
empty iterable collection, if this iterable collection has less than n
elements.
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.
the longest suffix of this traversable collection whose first element
does not satisfy the predicate p
.
Tests whether this sequence ends with the given sequence.
Tests whether this sequence ends with the given sequence.
Note: will not terminate for infinite-sized collections.
the sequence to test
true
if this sequence has that
as a suffix, false
otherwise.
Compares the receiver object (this
) with the argument object (that
) for equivalence.
Compares the receiver object (this
) with the argument object (that
) for equivalence.
Any implementation of this method should be an equivalence relation:
x
of type Any
, x.equals(x)
should return true
.x
and y
of type Any
, x.equals(y)
should return true
if and
only if y.equals(x)
returns true
.x
, y
, and z
of type Any
if x.equals(y)
returns true
and
y.equals(z)
returns true
, then x.equals(z)
should return true
. If you override this method, you should verify that your implementation remains an equivalence relation.
Additionally, when overriding this method it is usually necessary to override hashCode
to ensure that
objects which are "equal" (o1.equals(o2)
returns true
) hash to the same scala.Int.
(o1.hashCode.equals(o2.hashCode)
).
the object to compare against this object for equality.
true
if the receiver object is equivalent to the argument; false
otherwise.
Tests whether a predicate holds for at least one element of this iterable collection.
Tests whether a predicate holds for at least one element of this iterable collection.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
false
if this iterable collection is empty, otherwise true
if the given predicate p
holds for some of the elements of this iterable collection, otherwise false
Selects all elements of this traversable collection which satisfy a predicate.
Selects all elements of this traversable collection which satisfy a predicate.
the predicate used to test elements.
a new traversable collection consisting of all elements of this traversable collection that satisfy the given
predicate p
. The order of the elements is preserved.
Selects all elements of this traversable collection which do not satisfy a predicate.
Selects all elements of this traversable collection which do not satisfy a predicate.
the predicate used to test elements.
a new traversable collection consisting of all elements of this traversable collection that do not satisfy the given
predicate p
. The order of the elements is preserved.
Finds the first element of the iterable collection satisfying a predicate, if any.
Finds the first element of the iterable 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.
the predicate used to test elements.
an option value containing the first element in the iterable collection
that satisfies p
, or None
if none exists.
[use case] Builds a new collection by applying a function to all elements of this buffer proxy and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this buffer proxy 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 buffer proxy. 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)
the element type of the returned collection.
the function to apply to each element.
a new buffer proxy resulting from applying the given collection-valued function
f
to each element of this buffer proxy and concatenating the results.
[use case] Converts this buffer proxy of traversable collections into a buffer proxy formed by the elements of these traversable collections.
Converts this buffer proxy of traversable collections into a buffer proxy formed by the elements of these traversable collections.
The resulting collection's type will be guided by the static type of buffer proxy. 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)
the type of the elements of each traversable collection.
a new buffer proxy resulting from concatenating all element buffer proxys.
Folds the elements of this traversable or iterator using the specified associative binary operator.
Folds the elements of this traversable or iterator using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note: will not terminate for infinite-sized collections.
a type parameter for the binary operator, a supertype of A
.
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).
a binary operator that must be associative.
the result of applying the fold operator op
between all the elements and z
, or z
if this traversable or iterator is empty.
Applies a binary operator to a start value and all elements of this traversable or iterator, going left to right.
Applies a binary operator to a start value and all elements of this traversable or iterator, 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op
between consecutive elements of this traversable or iterator,
going left to right with the start value z
on the left:
op(...op(z, x_1), x_2, ..., x_n)
where x1, ..., xn
are the elements of this traversable or iterator.
Returns z
if this traversable or iterator is empty.
Applies a binary operator to all elements of this iterable collection and a start value, going right to left.
Applies a binary operator to all elements of this iterable 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op
between consecutive elements of this iterable 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, ..., xn
are the elements of this iterable collection.
Returns z
if this iterable collection is empty.
Tests whether a predicate holds for all elements of this iterable collection.
Tests whether a predicate holds for all elements of this iterable collection.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
true
if this iterable collection is empty or the given predicate p
holds for all elements of this iterable collection, otherwise false
.
[use case] Applies a function f
to all elements of this buffer proxy.
Applies a function f
to all elements of this buffer proxy.
Note: this method underlies the implementation of most other bulk operations. Subclasses should re-implement this method if a more efficient implementation exists.
the function that is applied for its side-effect to every element.
The result of function f
is discarded.
The generic builder that builds instances of Traversable at arbitrary element types.
The generic builder that builds instances of Traversable at arbitrary element types.
Partitions this traversable collection into a map of traversable collections according to some discriminator function.
Partitions this traversable collection into a map of traversable collections according to some discriminator function.
Note: this method is not re-implemented by views. This means when applied to a view it will always force the view and return a new traversable collection.
the type of keys returned by the discriminator function.
the discriminator function.
A map from keys to traversable collections such that the following invariant holds:
(xs groupBy f)(k) = xs filter (x => f(x) == k)
That is, every key k
is bound to a traversable collection of those elements x
for which f(x)
equals k
.
Partitions elements in fixed size iterable collections.
Partitions elements in fixed size iterable collections.
the number of elements per group
An iterator producing iterable collections of size size
, except the
last will be less than size size
if the elements don't divide evenly.
scala.collection.Iterator, method grouped
Tests whether this traversable collection is known to have a finite size.
Tests whether this traversable 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.
true
if this collection is known to have finite size,
false
otherwise.
Calculate a hash code value for the object.
Calculate a hash code value for the object.
The default hashing algorithm is platform dependent.
Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)
) yet
not be equal (o1.equals(o2)
returns false
). A degenerate implementation could always return 0
.
However, it is required that if two objects are equal (o1.equals(o2)
returns true
) that they have
identical hash codes (o1.hashCode.equals(o2.hashCode)
). Therefore, when overriding this method, be sure
to verify that the behavior is consistent with the equals
method.
the hash code value for this object.
Selects the first element of this iterable collection.
Selects the first element of this iterable collection.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the first element of this iterable collection.
NoSuchElementException
if the iterable collection is empty.
Optionally selects the first element.
Optionally selects the first element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the first element of this traversable collection if it is nonempty,
None
if it is empty.
[use case] Finds index of first occurrence of some value in this buffer proxy after or at some start index.
Finds index of first occurrence of some value in this buffer proxy after or at some start index.
the element value to search for.
the start index
the index >= from
of the first element of this buffer proxy that is equal (as determined by ==
)
to elem
, or -1
, if none exists.
[use case] Finds index of first occurrence of some value in this buffer proxy.
Finds index of first occurrence of some value in this buffer proxy.
the element value to search for.
the index of the first element of this buffer proxy that is equal (as determined by ==
)
to elem
, or -1
, if none exists.
Finds first index after or at a start index where this sequence contains a given sequence as a slice.
Finds first index after or at a start index where this sequence contains a given sequence as a slice.
Note: may not terminate for infinite-sized collections.
the sequence to test
the start index
the first index >= from
such that the elements of this sequence starting at this index
match the elements of sequence that
, or -1
of no such subsequence exists.
Finds first index where this sequence contains a given sequence as a slice.
Finds first index where this sequence contains a given sequence as a slice.
Note: may not terminate for infinite-sized collections.
the sequence to test
the first index such that the elements of this sequence starting at this index
match the elements of sequence that
, or -1
of no such subsequence exists.
Finds index of the first element satisfying some predicate after or at some start index.
Finds index of the first element satisfying some predicate after or at some start index.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
the start index
the index >= from
of the first element of this sequence that satisfies the predicate p
,
or -1
, if none exists.
Finds index of first element satisfying some predicate.
Finds index of first element satisfying some predicate.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
the index of the first element of this general sequence that satisfies the predicate p
,
or -1
, if none exists.
Produces the range of all indices of this sequence.
Produces the range of all indices of this sequence.
a Range
value from 0
to one less than the length of this sequence.
Selects all elements except the last.
Selects all elements except the last.
Note: might return different results for different runs, unless the underlying collection type is ordered.
a traversable collection consisting of all elements of this traversable collection except the last one.
UnsupportedOperationException
if the traversable collection is empty.
Iterates over the inits of this traversable collection.
Iterates over the inits of this traversable collection. The first value will be this
traversable collection and the final one will be an empty traversable collection, with the intervening
values the results of successive applications of init
.
an iterator over all the inits of this traversable collection
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
Inserts new elements at the index n
.
Inserts new elements at the index n
. Opposed to method
update
, this method will not replace an element with a
one. Instead, it will insert the new elements at index n
.
the index where a new element will be inserted.
the new elements to insert.
Inserts new elements at a given index into this buffer.
Inserts new elements at a given index into this buffer.
the index where new elements are inserted.
IndexOutOfBoundsException
if the index n
is not in the valid range
0 <= n <= length
.
Inserts new elements at the index n
.
Inserts new elements at the index n
. Opposed to method
update
, this method will not replace an element with a
one. Instead, it will insert a new element at index n
.
the index where a new element will be inserted.
the iterable object providing all elements to insert.
[use case] Computes the multiset intersection between this buffer proxy and another sequence.
Computes the multiset intersection between this buffer proxy and another sequence.
the sequence of elements to intersect with.
a new buffer proxy which contains all elements of this buffer proxy
which also appear in that
.
If an element value x
appears
n times in that
, then the first n occurrences of x
will be retained
in the result, but any following occurrences will be omitted.
Tests whether this general sequence contains given index.
Tests whether this general sequence contains given index.
The implementations of methods apply
and isDefinedAt
turn a Seq[A]
into
a PartialFunction[Int, A]
.
the index to test
true
if this general sequence contains an element at position idx
, false
otherwise.
Tests whether this sequence is empty.
Tests whether this sequence is empty.
true
if the sequence contain no elements, false
otherwise.
Tests whether this traversable collection can be repeatedly traversed.
Tests whether this traversable collection can be repeatedly traversed.
true
Creates a new iterator over all elements contained in this iterable object.
Creates a new iterator over all elements contained in this iterable object.
the new iterator
Selects the last element.
Selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
The last element of this traversable collection.
NoSuchElementException
If the traversable collection is empty.
[use case] Finds index of last occurrence of some value in this buffer proxy before or at a given end index.
Finds index of last occurrence of some value in this buffer proxy before or at a given end index.
the element value to search for.
the end index.
the index <= end
of the last element of this buffer proxy that is equal (as determined by ==
)
to elem
, or -1
, if none exists.
[use case] Finds index of last occurrence of some value in this buffer proxy.
Finds index of last occurrence of some value in this buffer proxy.
the element value to search for.
the index of the last element of this buffer proxy that is equal (as determined by ==
)
to elem
, or -1
, if none exists.
Finds last index before or at a given end index where this sequence contains a given sequence as a slice.
Finds last index before or at a given end index where this sequence contains a given sequence as a slice.
the sequence to test
the end index
the last index <= end
such that the elements of this sequence starting at this index
match the elements of sequence that
, or -1
of no such subsequence exists.
Finds last index where this sequence contains a given sequence as a slice.
Finds last index where this sequence contains a given sequence as a slice.
Note: will not terminate for infinite-sized collections.
the sequence to test
the last index such that the elements of this sequence starting a this index
match the elements of sequence that
, or -1
of no such subsequence exists.
Finds index of last element satisfying some predicate before or at given end index.
Finds index of last element satisfying some predicate before or at given end index.
the predicate used to test elements.
the index <= end
of the last element of this sequence that satisfies the predicate p
,
or -1
, if none exists.
Finds index of last element satisfying some predicate.
Finds index of last element satisfying some predicate.
Note: will not terminate for infinite-sized collections.
the predicate used to test elements.
the index of the last element of this general sequence that satisfies the predicate p
,
or -1
, if none exists.
Optionally selects the last element.
Optionally selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the last element of this traversable collection$ if it is nonempty,
None
if it is empty.
The length of the buffer proxy.
The length of the buffer proxy.
Note: xs.length
and xs.size
yield the same result.
the number of elements in this buffer proxy.
Compares the length of this sequence to a test value.
Compares the length of this sequence to a test value.
the test value that gets compared with the length.
A value x
where
x < 0 if this.length < len x == 0 if this.length == len x > 0 if this.length > len
The method as implemented here does not call length
directly; its running time
is O(length min len)
instead of O(length)
. The method should be overwritten
if computing length
is cheap.
Turns this partial function into a plain function returning an Option
result.
Turns this partial function into a plain function returning an Option
result.
a function that takes an argument x
to Some(this(x))
if this
is defined for x
, and to None
otherwise.
Function.unlift
[use case] Builds a new collection by applying a function to all elements of this buffer proxy.
Builds a new collection by applying a function to all elements of this buffer proxy.
the element type of the returned collection.
the function to apply to each element.
a new buffer proxy resulting from applying the given function
f
to each element of this buffer proxy and collecting the results.
[use case] Finds the largest element.
Finds the largest element.
the largest element of this buffer proxy.
[use case] 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.
The result type of the function f.
The measuring function.
the first element of this buffer proxy with the largest value measured by function f.
[use case] Finds the smallest element.
Finds the smallest element.
the smallest element of this buffer proxy
[use case] 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.
The result type of the function f.
The measuring function.
the first element of this buffer proxy with the smallest value measured by function f.
Displays all elements of this traversable or iterator in a string.
Displays all elements of this traversable or iterator in a string.
a string representation of this traversable or iterator. In the resulting string
the string representations (w.r.t. the method toString
)
of all elements of this traversable or iterator follow each other without any
separator string.
Displays all elements of this traversable or iterator in a string using a separator string.
Displays all elements of this traversable or iterator in a string using a separator string.
the separator string.
a string representation of this traversable or iterator. In the resulting string
the string representations (w.r.t. the method toString
)
of all elements of this traversable or iterator are separated by the string sep
.
List(1, 2, 3).mkString("|") = "1|2|3"
Displays all elements of this traversable or iterator in a string using start, end, and separator strings.
Displays all elements of this traversable or iterator in a string using start, end, and separator strings.
the starting string.
the separator string.
the ending string.
a string representation of this traversable or iterator. 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 traversable or iterator are separated by
the string sep
.
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Tests whether the traversable or iterator is not empty.
Tests whether the traversable or iterator is not empty.
true
if the traversable or iterator contains at least one element, false
otherwise.
Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.
Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.
the argument type of the fallback function
the result type of the fallback function
the fallback function
a partial function which has as domain the union of the domains
of this partial function and that
. The resulting partial function
takes x
to this(x)
where this
is defined, and to that(x)
where it is not.
[use case] A copy of this buffer proxy with an element value appended until a given target length is reached.
A copy of this buffer proxy with an element value appended until a given target length is reached.
the target length
the padding value
a new buffer proxy consisting of
all elements of this buffer proxy followed by the minimal number of occurrences of elem
so
that the resulting buffer proxy has a length of at least len
.
Returns a parallel implementation of this collection.
Returns a parallel implementation of this collection.
For most collection types, this method creates a new parallel collection by copying
all the elements. For these collection, par
takes linear time. Mutable collections
in this category do not produce a mutable parallel collection that has the same
underlying dataset, so changes in one collection will not be reflected in the other one.
Specific collections (e.g. ParArray
or mutable.ParHashMap
) override this default
behaviour by creating a parallel collection which shares the same underlying dataset.
For these collections, par
takes constant or sublinear time.
All parallel collections return a reference to themselves.
a parallel implementation of this collection
Partitions this traversable collection in two traversable collections according to a predicate.
Partitions this traversable collection in two traversable collections according to a predicate.
the predicate on which to partition.
a pair of traversable collections: the first traversable collection consists of all elements that
satisfy the predicate p
and the second traversable collection consists of all elements
that don't. The relative order of the elements in the resulting traversable collections
is the same as in the original traversable collection.
[use case] Produces a new buffer proxy where a slice of elements in this buffer proxy is replaced by another sequence.
Produces a new buffer proxy where a slice of elements in this buffer proxy is replaced by another sequence.
the index of the first replaced element
the number of elements to drop in the original buffer proxy
a new buffer proxy consisting of all elements of this buffer proxy
except that replaced
elements starting from from
are replaced
by patch
.
Iterates over distinct permutations.
Iterates over distinct permutations.
An Iterator which traverses the distinct permutations of this sequence.
"abb".permutations = Iterator(abb, bab, bba)
Returns the length of the longest prefix whose elements all satisfy some predicate.
Returns the length of the longest prefix whose elements all satisfy some predicate.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
the length of the longest prefix of this general sequence
such that every element of the segment satisfies the predicate p
.
Prepend an element to this list.
Prepend an element to this list.
the elements to prepend.
Prepends a number of elements provided by a traversable object.
Prepends a number of elements provided by a traversable object. The identity of the buffer is returned.
the traversable object.
[use case] Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the product of all elements in this buffer proxy of numbers of type Int
.
Instead of Int
, any other type T
with an implicit Numeric[T]
implementation
can be used as element type of the buffer proxy and as result type of product
.
Examples of such types are: Long
, Float
, Double
, BigInt
.
Returns the current evolving(!) state of this buffer as a read-only sequence.
Returns the current evolving(!) state of this buffer as a read-only sequence.
A sequence that forwards to this buffer for all its operations.
Reduces the elements of this traversable or iterator using the specified associative binary operator.
Reduces the elements of this traversable or iterator using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
A type parameter for the binary operator, a supertype of A
.
A binary operator that must be associative.
The result of applying reduce operator op
between all the elements if the traversable or iterator is nonempty.
UnsupportedOperationException
if this traversable or iterator is empty.
Applies a binary operator to all elements of this traversable or iterator, going left to right.
Applies a binary operator to all elements of this traversable or iterator, 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.
the result type of the binary operator.
the binary operator.
the result of inserting op
between consecutive elements of this traversable or iterator,
going left to right:
op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n)
where x1, ..., xn
are the elements of this traversable or iterator.
UnsupportedOperationException
if this traversable or iterator is empty.
Optionally applies a binary operator to all elements of this traversable or iterator, going left to right.
Optionally applies a binary operator to all elements of this traversable or iterator, 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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceLeft(op)
if this traversable or iterator is nonempty,
None
otherwise.
Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.
Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
A type parameter for the binary operator, a supertype of A
.
A binary operator that must be associative.
An option value containing result of applying reduce operator op
between all
the elements if the collection is nonempty, and None
otherwise.
Applies a binary operator to all elements of this iterable collection, going right to left.
Applies a binary operator to all elements of this iterable 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.
the result type of the binary operator.
the binary operator.
the result of inserting op
between consecutive elements of this iterable collection,
going right to left:
op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))
where x1, ..., xn
are the elements of this iterable collection.
UnsupportedOperationException
if this iterable collection is empty.
Optionally applies a binary operator to all elements of this traversable or iterator, going right to left.
Optionally applies a binary operator to all elements of this traversable or iterator, 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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceRight(op)
if this traversable or iterator is nonempty,
None
otherwise.
Removes the element on a given index position.
Removes the element on a given index position.
the index which refers to the element to delete.
the previous element at index n
Removes a number of elements from a given index position.
Removes a number of elements from a given index position.
the index which refers to the first element to remove.
the number of elements to remove.
IllegalArgumentException
if count < 0
.
IndexOutOfBoundsException
if the index n
is not in the valid range
0 <= n <= length - count
.
The collection of type traversable collection underlying this TraversableLike
object.
The collection of type traversable collection underlying this TraversableLike
object.
By default this is implemented as the TraversableLike
object itself,
but this can be overridden.
Returns new sequence with elements in reversed order.
Returns new sequence with elements in reversed order.
Note: will not terminate for infinite-sized collections.
A new sequence with all elements of this sequence in reversed order.
An iterator yielding elements in reversed order.
An iterator yielding elements in reversed order.
Note: will not terminate for infinite-sized collections.
Note: xs.reverseIterator
is the same as xs.reverse.iterator
but might be more efficient.
an iterator yielding the elements of this sequence in reversed order
[use case] Builds a new collection by applying a function to all elements of this buffer proxy and collecting the results in reversed order.
Builds a new collection by applying a function to all elements of this buffer proxy and collecting the results in reversed order.
Note: xs.reverseMap(f)
is the same as xs.reverse.map(f)
but might be more efficient.
the element type of the returned collection.
the function to apply to each element.
a new buffer proxy resulting from applying the given function
f
to each element of this buffer proxy and collecting the results in reversed order.
Composes this partial function with an action function which gets applied to results of this partial function.
Composes this partial function with an action function which gets applied to results of this partial function. The action function is invoked only for its side effects; its result is ignored.
Note that expression pf.runWith(action)(x)
is equivalent to
if(pf isDefinedAt x) { action(pf(x)); true } else false
except that runWith
is implemented via applyOrElse
and thus potentially more efficient.
Using runWith
avoids double evaluation of pattern matchers and guards for partial function literals.
the action function
a function which maps arguments x
to isDefinedAt(x)
. The resulting function
runs action(this(x))
where this
is defined.
2.10
applyOrElse
.
[use case] Checks if the other iterable collection contains the same elements in the same order as this buffer proxy.
Checks if the other iterable collection contains the same elements in the same order as this buffer proxy.
the collection to compare with.
true
, if both collections contain the same elements in the same order, false
otherwise.
Computes a prefix scan of the elements of the collection.
Computes a prefix scan of the elements of the collection.
Note: The neutral element z
may be applied more than once.
element type of the resulting collection
type of the resulting collection
neutral element for the operator op
the associative operator for the scan
combiner factory which provides a combiner
a new traversable collection containing the prefix scan of the elements in this traversable collection
Produces a collection containing cumulative results of applying the operator going left to right.
Produces a collection containing cumulative results of applying the operator going left to right.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the type of the elements in the resulting collection
the actual type of the resulting collection
the initial value
the binary operator applied to the intermediate result and the element
an implicit value of class CanBuildFrom
which determines
the result class That
from the current representation type Repr
and
and the new element type B
.
collection with intermediate results
Produces a collection containing cumulative results of applying the operator going right to left.
Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result.
Note: will not terminate for infinite-sized collections.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Example:
List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
the type of the elements in the resulting collection
the actual type of the resulting collection
the initial value
the binary operator applied to the intermediate result and the element
an implicit value of class CanBuildFrom
which determines
the result class That
from the current representation type Repr
and
and the new element type B
.
collection with intermediate results
(Changed in version 2.9.0) The behavior of scanRight
has changed. The previous behavior can be reproduced with scanRight.reverse.
Computes length of longest segment whose elements all satisfy some predicate.
Computes length of longest segment whose elements all satisfy some predicate.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
the index where the search starts.
the length of the longest segment of this sequence starting from index from
such that every element of the segment satisfies the predicate p
.
A version of this collection with all of the operations implemented sequentially (i.e., in a single-threaded manner).
A version of this collection with all of the operations implemented sequentially (i.e., in a single-threaded manner).
This method returns a reference to this collection. In parallel collections, it is redefined to return a sequential implementation of this collection. In both cases, it has O(1) complexity.
a sequential view of the collection.
The size of this sequence, equivalent to length
.
The size of this sequence, equivalent to length
.
Note: will not terminate for infinite-sized collections.
the number of elements in this sequence.
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.
a iterable collection containing the elements greater than or equal to
index from
extending up to (but not including) index until
of this iterable collection.
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
the number of elements per group
the distance between the first elements of successive groups
An iterator producing iterable collections of size size
, except the
last and the only element will be truncated if there are
fewer elements than size.
scala.collection.Iterator, method sliding
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.) "Sliding window" step is 1 by default.
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.) "Sliding window" step is 1 by default.
the number of elements per group
An iterator producing iterable collections of size size
, except the
last and the only element will be truncated if there are
fewer elements than size.
scala.collection.Iterator, method sliding
Sorts this Seq
according to the Ordering which results from transforming
an implicitly given Ordering with a transformation function.
Sorts this Seq
according to the Ordering which results from transforming
an implicitly given Ordering with a transformation function.
the target type of the transformation f
, and the type where
the ordering ord
is defined.
the transformation function mapping elements
to some other domain B
.
the ordering assumed on domain B
.
a sequence consisting of the elements of this sequence
sorted according to the ordering where x < y
if
ord.lt(f(x), f(y))
.
val words = "The quick brown fox jumped over the lazy dog".split(' ') // this works because scala.Ordering will implicitly provide an Ordering[Tuple2[Int, Char]] words.sortBy(x => (x.length, x.head)) res0: Array[String] = Array(The, dog, fox, the, lazy, over, brown, quick, jumped)
scala.math.Ordering Note: will not terminate for infinite-sized collections.
Sorts this sequence according to a comparison function.
Sorts this sequence according to a comparison function.
Note: will not terminate for infinite-sized collections.
The sort is stable. That is, elements that are equal (as determined by
lt
) appear in the same order in the sorted sequence as in the original.
the comparison function which tests whether its first argument precedes its second argument in the desired ordering.
a sequence consisting of the elements of this sequence
sorted according to the comparison function lt
.
List("Steve", "Tom", "John", "Bob").sortWith(_.compareTo(_) < 0) = List("Bob", "John", "Steve", "Tom")
Sorts this sequence according to an Ordering.
Sorts this sequence according to an Ordering.
The sort is stable. That is, elements that are equal (as determined by
lt
) appear in the same order in the sorted sequence as in the original.
the ordering to be used to compare elements.
a sequence consisting of the elements of this sequence
sorted according to the ordering ord
.
Splits this traversable collection into a prefix/suffix pair according to a predicate.
Splits this traversable 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.
a pair consisting of the longest prefix of this traversable collection whose
elements all satisfy p
, and the rest of this traversable collection.
Splits this traversable collection into two at a given position.
Splits this traversable collection into two 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.
the position at which to split.
a pair of traversable collections consisting of the first n
elements of this traversable collection, and the other elements.
Tests whether this sequence contains the given sequence at a given index.
Tests whether this sequence contains the given sequence at a given index.
Note: If the both the receiver object this
and the argument
that
are infinite sequences this method may not terminate.
the sequence to test
the index where the sequence is searched.
true
if the sequence that
is contained in this sequence at
index offset
, otherwise false
.
Tests whether this general sequence starts with the given sequence.
Tests whether this general sequence starts with the given sequence.
the sequence to test
true
if this collection has that
as a prefix, false
otherwise.
Defines the prefix of this object's toString
representation.
Defines the prefix of this object's toString
representation.
a string representation which starts the result of toString
applied to this set.
Unless overridden this is simply "Buffer"
.
[use case] Sums up the elements of this collection.
Sums up the elements of this collection.
the sum of all elements in this buffer proxy of numbers of type Int
.
Instead of Int
, any other type T
with an implicit Numeric[T]
implementation
can be used as element type of the buffer proxy and as result type of sum
.
Examples of such types are: Long
, Float
, Double
, BigInt
.
Selects all elements except the first.
Selects all elements except the first.
Note: might return different results for different runs, unless the underlying collection type is ordered.
a traversable collection consisting of all elements of this traversable collection except the first one.
`UnsupportedOperationException`
if the traversable collection is empty.
Iterates over the tails of this traversable collection.
Iterates over the tails of this traversable collection. The first value will be this
traversable collection and the final one will be an empty traversable collection, with the intervening
values the results of successive applications of tail
.
an iterator over all the tails of this traversable collection
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Selects first n elements.
Selects first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the number of elements to take from this iterable collection.
a iterable collection consisting only of the first n
elements of this iterable collection,
or else the whole iterable collection, if it has less than n
elements.
Selects last n elements.
Selects last n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the number of elements to take
a iterable collection consisting only of the last n
elements of this iterable collection, or else the
whole iterable collection, if it has less than n
elements.
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.
the longest prefix of this iterable collection whose elements all satisfy
the predicate p
.
[use case] Converts this buffer proxy into another by copying all elements.
Converts this buffer proxy into another by copying all elements.
The collection type to build.
a new collection containing all elements of this buffer proxy.
[use case] Converts this buffer proxy to an array.
Converts this buffer proxy to an array.
an array containing all elements of this buffer proxy.
An ClassTag
must be available for the element type of this buffer proxy.
Uses the contents of this traversable or iterator to create a new mutable buffer.
Uses the contents of this traversable or iterator to create a new mutable buffer.
Note: will not terminate for infinite-sized collections.
a buffer containing all elements of this traversable or iterator.
Converts this traversable or iterator to an indexed sequence.
Converts this traversable or iterator to an indexed sequence.
Note: will not terminate for infinite-sized collections.
an indexed sequence containing all elements of this traversable or iterator.
Returns this iterable collection as an iterable collection.
Returns this iterable collection as an iterable collection.
A new collection will not be built; lazy collections will stay lazy.
Note: will not terminate for infinite-sized collections.
an Iterable
containing all elements of this iterable collection.
Returns an Iterator over the elements in this iterable collection.
Returns an Iterator over the elements in this iterable collection. Produces the same
result as iterator
.
Note: will not terminate for infinite-sized collections.
an Iterator containing all elements of this iterable collection.
Converts this traversable or iterator to a list.
Converts this traversable or iterator to a list.
Note: will not terminate for infinite-sized collections.
a list containing all elements of this traversable or iterator.
[use case] Converts this buffer proxy to a map.
Converts this buffer proxy to a map. This method is unavailable unless the elements are members of Tuple2, each ((T, U)) becoming a key-value pair in the map. Duplicate keys will be overwritten by later keys: if this is an unordered collection, which key is in the resulting map is undefined.
a map of type immutable.Map[T, U]
containing all key/value pairs of type (T, U)
of this buffer proxy.
Converts this sequence to a sequence.
Converts this sequence to a sequence.
Note: will not terminate for infinite-sized collections.
A new collection will not be built; in particular, lazy sequences will stay lazy.
a sequence containing all elements of this sequence.
Converts this traversable or iterator to a set.
Converts this traversable or iterator to a set.
Note: will not terminate for infinite-sized collections.
a set containing all elements of this traversable or iterator.
Converts this iterable collection to a stream.
Converts this iterable collection to a stream.
a stream containing all elements of this iterable collection.
Returns a string representation of the object.
Converts this traversable collection to an unspecified Traversable.
Converts this traversable collection to an unspecified Traversable. Will return the same collection if this instance is already Traversable.
Note: will not terminate for infinite-sized collections.
a Traversable containing all elements of this traversable collection.
Converts this traversable or iterator to a Vector.
Converts this traversable or iterator to a Vector.
Note: will not terminate for infinite-sized collections.
a vector containing all elements of this traversable or iterator.
Applies a transformation function to all values contained in this sequence.
Applies a transformation function to all values contained in this sequence. The transformation function produces new values from existing elements.
the transformation to apply
the sequence itself.
Transposes this collection of traversable collections into a collection of collections.
Transposes this collection of traversable collections into a collection of collections.
The resulting collection's type will be guided by the static type of collection. For example:
val xs = List( Set(1, 2, 3), Set(4, 5, 6)).transpose // xs == List( // List(1, 4), // List(2, 5), // List(3, 6)) val ys = Vector( List(1, 2, 3), List(4, 5, 6)).transpose // ys == Vector( // Vector(1, 4), // Vector(2, 5), // Vector(3, 6))
the type of the elements of each traversable collection.
an implicit conversion which asserts that the
element type of this collection is a Traversable
.
a two-dimensional collection of collections which has as nth row the nth column of this collection.
(Changed in version 2.9.0) transpose
throws an IllegalArgumentException
if collections are not uniformly sized.
IllegalArgumentException
if all collections in this collection
are not of the same size.
Removes the last n elements of this buffer.
Removes the last n elements of this buffer.
the number of elements to remove from the end of this buffer.
Removes the first n elements of this buffer.
Removes the first n elements of this buffer.
the number of elements to remove from the beginning of this buffer.
[use case] Produces a new sequence which contains all elements of this buffer proxy and also all elements of a given sequence.
Produces a new sequence which contains all elements of this buffer proxy and also all elements of
a given sequence. xs union ys
is equivalent to xs ++ ys
.
Another way to express this
is that xs union ys
computes the order-preserving multi-set union of xs
and ys
.
union
is hence a counter-part of diff
and intersect
which also work on multi-sets.
the sequence to add.
a new buffer proxy which contains all elements of this buffer proxy
followed by all elements of that
.
Converts this collection of pairs into two collections of the first and second half of each pair.
Converts this collection of pairs into two collections of the first and second half of each pair.
val xs = Traversable( (1, "one"), (2, "two"), (3, "three")).unzip // xs == (Traversable(1, 2, 3), // Traversable(one, two, three))
the type of the first half of the element pairs
the type of the second half of the element pairs
an implicit conversion which asserts that the element type of this collection is a pair.
a pair of collections, containing the first, respectively second half of each element pair of this collection.
Converts this collection of triples into three collections of the first, second, and third element of each triple.
Converts this collection of triples into three collections of the first, second, and third element of each triple.
val xs = Traversable( (1, "one", '1'), (2, "two", '2'), (3, "three", '3')).unzip3 // xs == (Traversable(1, 2, 3), // Traversable(one, two, three), // Traversable(1, 2, 3))
the type of the first member of the element triples
the type of the second member of the element triples
the type of the third member of the element triples
an implicit conversion which asserts that the element type of this collection is a triple.
a triple of collections, containing the first, second, respectively third member of each element triple of this collection.
Replace element at index n
with the new element newelem
.
Replace element at index n
with the new element newelem
.
the index of the element to replace.
the new element.
[use case] A copy of this buffer proxy with one single replaced element.
A copy of this buffer proxy with one single replaced element.
the position of the replacement
the replacing element
a copy of this buffer proxy with the element at position index
replaced by elem
.
Creates a non-strict view of a slice of this sequence.
Creates a non-strict view of a slice of this sequence.
Note: the difference between view
and slice
is that view
produces
a view of the current sequence, whereas slice
produces a new sequence.
Note: view(from, to)
is equivalent to view.slice(from, to)
the index of the first element of the view
the index of the element following the view
a non-strict view of a slice of this sequence, starting at index from
and extending up to (but not including) index until
.
Creates a non-strict view of this sequence.
Creates a non-strict view of this sequence.
a non-strict view of this sequence.
Creates a non-strict filter of this traversable collection.
Creates a non-strict filter of this traversable collection.
Note: the difference between c filter p
and c withFilter p
is that
the former creates a new collection, whereas the latter only
restricts the domain of subsequent map
, flatMap
, foreach
,
and withFilter
operations.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the predicate used to test elements.
an object of class WithFilter
, which supports
map
, flatMap
, foreach
, and withFilter
operations.
All these operations apply to those elements of this traversable collection
which satisfy the predicate p
.
[use case] Returns a buffer proxy formed from this buffer proxy and another iterable collection by combining corresponding elements in pairs.
Returns a buffer proxy formed from this buffer proxy and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.
the type of the second half of the returned pairs
The iterable providing the second half of each result pair
a new buffer proxy containing pairs consisting of
corresponding elements of this buffer proxy and that
. The length
of the returned collection is the minimum of the lengths of this buffer proxy and that
.
[use case] Returns a buffer proxy formed from this buffer proxy and another iterable collection by combining corresponding elements in pairs.
Returns a buffer proxy formed from this buffer proxy and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.
the type of the second half of the returned pairs
The iterable providing the second half of each result pair
the element to be used to fill up the result if this buffer proxy is shorter than that
.
the element to be used to fill up the result if that
is shorter than this buffer proxy.
a new buffer proxy containing pairs consisting of
corresponding elements of this buffer proxy and that
. The length
of the returned collection is the maximum of the lengths of this buffer proxy and that
.
If this buffer proxy is shorter than that
, thisElem
values are used to pad the result.
If that
is shorter than this buffer proxy, thatElem
values are used to pad the result.
[use case] Zips this buffer proxy with its indices.
Zips this buffer proxy with its indices.
A new buffer proxy containing pairs consisting of all elements of this
buffer proxy paired with their index. Indices start at 0
.
List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))
(bufferProxy: MonadOps[A]).filter(p)
(bufferProxy: MonadOps[A]).flatMap(f)
(bufferProxy: MonadOps[A]).map(f)
(bufferProxy: MonadOps[A]).withFilter(p)
Send a message to this scriptable object.
Send a message to this scriptable object.
the message to send.
(Since version 2.11.0) Scripting is deprecated.
This is a simple proxy class for `scala.collection.mutable.Buffer`. It is most useful for assembling customized set abstractions dynamically using object composition and forwarding.
type of the elements the buffer proxy contains.
(Since version 2.11.0) Proxying is deprecated due to lack of use and compiler-level support.
1.0, 16/04/2004
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