TakenWhile

Applies a binary operator to a start value and all elements of this general sequence, 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 = LinkedList(1,2,3,4)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(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.

Applies a binary operator to all elements of this general sequence 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 = LinkedList(1,2,3,4)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)

scala> val b = (a :\ 5)(_+_)
b: Int = 15

scala> val c = (a :\ 5)((x,y) => x + y)
c: Int = 15

Aggregates the results of applying an operator to subsequent elements.

This is a more general form of fold and reduce. It has similar semantics, but does not require the result to be a supertype of the element type. It traverses the elements in different partitions sequentially, using seqop to update the result, and then applies combop to results from different partitions. The implementation of this operation may operate on an arbitrary number of collection partitions, so combop may be invoked an arbitrary number of times.

For example, one might want to process some elements and then produce a Set. In this case, seqop would process an element and append it to the list, while combop would concatenate two lists from different partitions together. The initial value z would be an empty set.

pc.aggregate(Set[Int]())(_ += process(_), _ ++ _)

Another example is calculating geometric mean from a collection of doubles (one would typically require big doubles for this).

A method that should be called from every well-designed equals method that is open to be overridden in a subclass. See Programming in Scala, Chapter 28 for discussion and design.

Tests whether every element of this general sequence relates to the corresponding element of another sequence by satisfying a test predicate.

Counts the number of elements in the general sequence which satisfy a predicate.

Builds a new general sequence from this general sequence without any duplicate elements.

Note: will not terminate for infinite-sized collections.

Selects all elements except first n ones.

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

Drops longest prefix of elements that satisfy a predicate.

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

Tests whether this general sequence ends with the given sequence.

Note: will not terminate for infinite-sized collections.

Selects all elements of this general sequence which satisfy a predicate.

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

Finds the first element of the general sequence 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.

Folds the elements of this general sequence using the specified associative binary operator.

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

Applies a binary operator to a start value and all elements of this general sequence, 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.

Applies a binary operator to all elements of this general sequence 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.

Partitions this general sequence into a map of general sequences 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 general sequence.

Selects the first element of this general sequence.

Optionally selects the first element.

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

Finds index of the first element satisfying some predicate after or at some start index.

Note: may not terminate for infinite-sized collections.

Selects all elements except the last.

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

Tests whether this general sequence is empty.

Tests whether this general sequence can be repeatedly traversed.

Selects the last element.

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

Finds index of last element satisfying some predicate before or at given end index.

Optionally selects the last element.

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

Displays all elements of this general sequence in a string.

Displays all elements of this general sequence in a string using a separator string.

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

Tests whether the general sequence is not empty.

The default par implementation uses the combiner provided by this method to create a new parallel collection.

Partitions this general sequence in two general sequences according to a predicate.

Reduces the elements of this general sequence using the specified associative binary operator.

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

Optionally applies a binary operator to all elements of this general sequence, 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.

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

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

Applies a binary operator to all elements of this general sequence, 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.

Optionally applies a binary operator to all elements of this general sequence, 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.

Returns new general sequence wih elements in reversed order.

Note: will not terminate for infinite-sized collections.

Computes a prefix scan of the elements of the collection.

Note: The neutral element z may be applied more than once.

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.

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)

Computes length of longest segment whose elements all satisfy some predicate.

Note: may not terminate for infinite-sized collections.

The size of this general sequence.

Note: will not terminate for infinite-sized collections.

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.

Splits this general sequence 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.

Splits this general sequence 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.

Tests whether this general 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.

Selects all elements except the first.

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

Selects first n elements.

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

Takes longest prefix of elements that satisfy a predicate.

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

Converts this general sequence to a mutable buffer.

Note: will not terminate for infinite-sized collections.

Converts this general sequence to an indexed sequence.

Note: will not terminate for infinite-sized collections.

Converts this general sequence to an iterable collection. Note that the choice of target Iterable is lazy in this default implementation as this TraversableOnce may be lazy and unevaluated (i.e. it may be an iterator which is only traversable once).

Note: will not terminate for infinite-sized collections.

Returns an Iterator over the elements in this general sequence. Will return the same Iterator if this instance is already an Iterator.

Note: will not terminate for infinite-sized collections.

Converts this general sequence to a list.

Note: will not terminate for infinite-sized collections.

Converts this general sequence to a sequence. As with toIterable, it's lazy in this default implementation, as this TraversableOnce may be lazy and unevaluated.

Note: will not terminate for infinite-sized collections.

Converts this general sequence to a set.

Note: will not terminate for infinite-sized collections.

Converts this general sequence to a stream.

Note: will not terminate for infinite-sized collections.

Converts this general sequence to an unspecified Traversable. Will return the same collection if this instance is already Traversable.

Note: will not terminate for infinite-sized collections.

Converts this general sequence to a Vector.

Note: will not terminate for infinite-sized collections.

Test two objects for inequality.

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

Returns a new general sequence containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the general sequence is the most specific superclass encompassing the element types of the two operands.

Example:

scala> val a = LinkedList(1)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1)

scala> val b = LinkedList(2)
b: scala.collection.mutable.LinkedList[Int] = LinkedList(2)

scala> val c = a ++ b
c: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)

scala> val d = LinkedList('a')
d: scala.collection.mutable.LinkedList[Char] = LinkedList(a)

scala> val e = c ++ d
e: scala.collection.mutable.LinkedList[AnyVal] = LinkedList(1, 2, a)

A copy of the general sequence 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 general sequence is not modified, so you will want to capture the result.

Example:

scala> val x = LinkedList(1)
x: scala.collection.mutable.LinkedList[Int] = LinkedList(1)

scala> val y = 2 +: x
y: scala.collection.mutable.LinkedList[Int] = LinkedList(2, 1)

scala> println(x)
LinkedList(1)

A copy of this general sequence with an element appended.

A mnemonic for +: vs. :+ is: the COLon goes on the COLlection side.

Note: will not terminate for infinite-sized collections.

Example:

scala> import scala.collection.mutable.LinkedList
import scala.collection.mutable.LinkedList

scala> val a = LinkedList(1)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1)

scala> val b = a :+ 2
b: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)

scala> println(a)
LinkedList(1)

Test two objects for equality. The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

Selects an element by its index in the general sequence.

Example:

scala> val x = LinkedList(1, 2, 3, 4, 5)
x: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4, 5)

scala> x(3)
res1: Int = 4

Cast the receiver object to be of type T0.

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

Create a copy of the receiver object.

The default implementation of the clone method is platform dependent.

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

The factory companion object that builds instances of class GenSeq. (or its Iterable superclass where class GenSeq is not a Seq.)

Copies values of this general sequence to an array. Fills the given array xs with values of this general sequence, beginning at index start. Copying will stop once either the end of the current general sequence is reached, or the end of the array is reached.

Note: will not terminate for infinite-sized collections.

Copies values of this general sequence to an array. Fills the given array xs with values of this general sequence. Copying will stop once either the end of the current general sequence is reached, or the end of the array is reached.

Note: will not terminate for infinite-sized collections.

Computes the multiset difference between this general sequence and another sequence.

Note: will not terminate for infinite-sized collections.

Tests whether the argument (arg0) is a reference to the receiver object (this).

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

• It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.
• For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false.
• null.eq(null) returns true.

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

The equals method for arbitrary sequences. Compares this sequence to some other object.

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

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

Builds a new collection by applying a function to all elements of this general sequence 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 general sequence. 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 a 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)

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

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

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

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

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

The generic builder that builds instances of GenSeq at arbitrary element types.

A representation that corresponds to the dynamic class of the receiver object.

The nature of the representation is platform dependent.

Hashcodes for GenSeq produce a value from the hashcodes of all the elements of the general sequence.

Finds index of first occurrence of some value in this general sequence after or at some start index.

Note: may not terminate for infinite-sized collections.

Finds index of first occurrence of some value in this general sequence.

Note: may not terminate for infinite-sized collections.

Finds index of first element satisfying some predicate.

Note: may not terminate for infinite-sized collections.

Computes the multiset intersection between this general sequence and another sequence.

Note: may not terminate for infinite-sized collections.

Tests whether this general sequence contains given index.

The implementations of methods apply and isDefinedAt turn a Seq[A] into a PartialFunction[Int, A].

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

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

Finds index of last occurrence of some value in this general sequence before or at a given end index.

Finds index of last occurrence of some value in this general sequence.

Note: will not terminate for infinite-sized collections.

Finds index of last element satisfying some predicate.

Note: will not terminate for infinite-sized collections.

The length of the general sequence.

Note: will not terminate for infinite-sized collections.

Note: xs.length and xs.size yield the same result.

Builds a new collection by applying a function to all elements of this general sequence.

Finds the largest element.

Finds the smallest element.

Equivalent to !(this eq that).

The builder that builds instances of type GenSeq[A]

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

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

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

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.

Produces a new general sequence where a slice of elements in this general sequence is replaced by another sequence.

Returns the length of the longest prefix whose elements all satisfy some predicate.

Note: may not terminate for infinite-sized collections.

Multiplies up the elements of this collection.

Builds a new collection by applying a function to all elements of this general sequence and collecting the results in reversed order.

Note: will not terminate for infinite-sized collections.

Note: xs.reverseMap(f) is the same as xs.reverse.map(f) but might be more efficient.

Checks if the other iterable collection contains the same elements in the same order as this general sequence.

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

Note: will not terminate for infinite-sized collections.

Tests whether this general sequence starts with the given sequence.

Defines the prefix of this object's toString representation.

Sums up the elements of this collection.

Converts this general sequence into another by copying all elements.

Note: will not terminate for infinite-sized collections.

Converts this general sequence to an array.

Note: will not terminate for infinite-sized collections.

Converts this general sequence 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.

Note: will not terminate for infinite-sized collections.

Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

Transposes this general sequence of traversable collections into a general sequence of general sequences.

Produces a new sequence which contains all elements of this general sequence 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-presevring multi-set union of xs and ys. union is hence a counter-part of diff and intersect which also work on multi-sets.

Note: will not terminate for infinite-sized collections.

Converts this general sequence of pairs into two collections of the first and second half of each pair.

Converts this general sequence of triples into three collections of the first, second, and third element of each triple.

A copy of this general sequence with one single replaced element.

Returns a general sequence formed from this general sequence 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.

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

Returns a general sequence formed from this general sequence 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.

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

Zips this general sequence with its indices.

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

A syntactic sugar for out of order folding. See fold.

Example:

scala> val a = LinkedList(1,2,3,4)
a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)

scala> val b = (a /:\ 5)(_+_)
b: Int = 15