The empty map of the same type as this map

Defines how to turn a given Iterable[A] into a collection of type C.

This process can be done in a strict way or a non-strict way (ie. without evaluating the elements of the resulting collections). In other words, this methods defines the evaluation model of the collection.

Optionally returns the value associated with a key.

Iterator can be used only once

Creates an iterator over all the key/value pairs contained in this map having a key greater than or equal to start according to the ordering of this map. x.iteratorFrom(y) is equivalent to but often more efficient than x.from(y).iterator.

Creates an iterator over all the keys(or elements) contained in this collection greater than or equal to start according to the ordering of this collection. x.keysIteratorFrom(y) is equivalent to but often more efficient than x.from(y).keysIterator.

Creates a ranged projection of this collection. Any mutations in the ranged projection will update this collection and vice versa.

Note: keys are not guaranteed to be consistent between this collection and the projection. This is the case for buffers where indexing is relative to the projection.

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.

Alias for concat

Alias for concat

Alias for concat

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

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

Example:

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

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

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

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

Example:

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

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

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

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

Example:

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

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

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

Composes this partial function with a transformation function that gets applied to results of this partial function.

Retrieves the value which is associated with the given key. This method invokes the default method of the map if there is no mapping from the given key to a value. Unless overridden, the default method throws a NoSuchElementException.

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:

• combining partial functions into orElse/andThen chains does not lead to excessive apply/isDefinedAt evaluation
• lift and unlift do not evaluate source functions twice on each invocation
• runWith 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.

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.

Defines the prefix of this object's toString representation.

It is recommended to return the name of the concrete collection type, but not implementation subclasses. For example, for ListMap this method should return "ListMap", not "Map" (the supertype) or "Node" (an implementation subclass).

It is recommended to overwrite this method even if the default implementation returns the correct name, to avoid the implementation using reflection.

Create a copy of the receiver object.

The default implementation of the clone method is platform dependent.

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

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

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

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

$mayNotTerminateInf $orderDependent

Composes two instances of Function1 in a new Function1, with this function applied last.

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

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

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

Tests whether this map contains a binding for a key.

Note: will not terminate for infinite-sized collections.

Note: will not terminate for infinite-sized collections.

Counts the number of elements in the $coll which satisfy a predicate.

Defines the default value computation for the map, returned when a key is not found The method implemented here throws an exception, but it might be overridden in subclasses.

Selects all elements except first n ones.

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

The rest of the collection without its n last elements. For linear, immutable collections this should avoid making a copy.

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

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

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

See also equals in scala.Any.

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

$mayNotTerminateInf

Selects all elements of this iterable collection which satisfy a predicate.

Filters this map by retaining only keys satisfying a predicate.

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

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.

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

$mayNotTerminateInf $orderDependent

Returns the first key of the collection.

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

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

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

For example:

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

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

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

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

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

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

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

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

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

$willNotTerminateInf $orderDependentFold

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

$willNotTerminateInf $orderDependentFold

Tests whether a predicate holds for all elements of this $coll.

$mayNotTerminateInf

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

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

Creates a ranged projection of this collection with no upper-bound.

Similar to fromSpecificIterable, but for a (possibly) different type of element. Note that the return type is now CC[E].

Returns the runtime class representation of the object.

Returns the value associated with a key, or a default value if the key is not contained in the map.

Partitions this iterable collection into a map of iterable collections according to some discriminator function.

Note: When applied to a view or a lazy collection it will always force the elements.

Partitions this iterable collection into a map of iterable collections according to a discriminator function key. Each element in a group is transformed into a value of type B using the value function.

It is equivalent to groupBy(key).mapValues(_.map(f)), but more efficient.

case class User(name: String, age: Int)

def namesByAge(users: Seq[User]): Map[Int, Seq[String]] =
  users.groupMap(_.age)(_.name)

Partitions this iterable collection into a map according to a discriminator function key. All the values that have the same discriminator are then transformed by the value function and then reduced into a single value with the reduce function.

It is equivalent to groupBy(key).mapValues(_.map(f).reduce(reduce)), but more efficient.

def occurrences[A](as: Seq[A]): Map[A, Int] =
  as.groupMapReduce(identity)(_ => 1)(_ + _)

Partitions elements in fixed size iterable collections.

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

Selects the first element of this iterable collection.

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

Optionally selects the first element.

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

The initial part of the collection without its last element.

Iterates over the inits of this iterable collection. The first value will be this iterable collection and the final one will be an empty iterable collection, with the intervening values the results of successive applications of init.

Tests whether this map contains a binding for a key. This method, which implements an abstract method of trait PartialFunction, is equivalent to contains.

Tests whether the $coll is empty.

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

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.

Collects all keys of this map in a set.

Collects all keys of this map in an iterable collection.

Creates an iterator for all keys.

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

Selects the last element.

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

Returns the last key of the collection.

Optionally selects the last element.

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

Turns this partial function into a plain function returning an Option result.

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

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

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

Similar to fromIterable, but returns a Map collection type. Note that the return type is now CC[K2, V2] aka MapCC[K2, V2] rather than IterableCC[(K2, V2)].

Transforms this map by applying a function to every retrieved value.

Finds the largest element.

Find the element with largest key less than a given key.

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

Finds the smallest element.

Find the element with smallest key larger than or equal to a given key.

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

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

Displays all elements of this $coll in a string.

Displays all elements of this $coll in a string using a separator string.

Equivalent to !(this eq that).

Tests whether the $coll is not empty.

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.

Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.

A pair of, first, all elements that satisfy prediacte p and, second, all elements that do not. Interesting because it splits a collection in two.

The default implementation provided here needs to traverse the collection twice. Strict collections have an overridden version of partition in Buildable, which requires only a single traversal.

Multiplies up the elements of this collection.

Creates a ranged projection of this collection with both a lower-bound and an upper-bound.

Create a range projection of this collection with no lower-bound.

Reduces the elements of this $coll using the specified associative binary operator.

$undefinedorder

Applies a binary operator to all elements of this $coll, going left to right. $willNotTerminateInf $orderDependentFold

Optionally applies a binary operator to all elements of this $coll, going left to right. $willNotTerminateInf $orderDependentFold

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

$undefinedorder

Applies a binary operator to all elements of this $coll, going right to left. $willNotTerminateInf $orderDependentFold

Optionally applies a binary operator to all elements of this $coll, going right to left. $willNotTerminateInf $orderDependentFold

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.

Computes a prefix scan of the elements of the collection.

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

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

Note: will not terminate for infinite-sized collections.

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

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 size of this $coll.

$willNotTerminateInf

Selects an interval of elements. The returned iterable 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.

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 "sliding window" step is set to one.

Similar to mapFromIterable, but returns a SortedMap collection type. Note that the return type is now CC[K2, V2] aka SortedMapCC[K2, V2] rather than MapCC[(K2, V2)].

Splits this iterable 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.

Splits this iterable 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.

Sums up the elements of this collection.

The rest of the collection without its first element.

Iterates over the tails of this iterable collection. The first value will be this iterable collection and the final one will be an empty iterable collection, with the intervening values the results of successive applications of tail.

Selects first n elements.

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

A collection containing the last n elements of this collection.

Takes longest prefix of elements that satisfy a predicate.

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

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

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

Convert collection to array.

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 iterable collection of iterable collections into a iterable collection of iterable collections.

The resulting collection's type will be guided by the static type of iterable 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))

Creates a ranged projection of this collection with no lower-bound.

Converts this iterable collection of pairs into two collections of the first and second half of each pair.

val xs = Iterable(
           (1, "one"),
           (2, "two"),
           (3, "three")).unzip
// xs == (Iterable(1, 2, 3),
//        Iterable(one, two, three))

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

val xs = Iterable(
           (1, "one", '1'),
           (2, "two", '2'),
           (3, "three", '3')).unzip3
// xs == (Iterable(1, 2, 3),
//        Iterable(one, two, three),
//        Iterable(1, 2, 3))

Collects all values of this map in an iterable collection.

Creates an iterator for all values in this map.

Creates an iterator over all the values contained in this map that are associated with a key greater than or equal to start according to the ordering of this map. x.valuesIteratorFrom(y) is equivalent to but often more efficient than x.from(y).valuesIterator.

A view over the elements of this collection.

Creates a non-strict filter of this map.

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.

Returns a iterable collection formed from this iterable collection 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.

Returns a iterable collection formed from this iterable collection 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.

Zips this iterable collection with its indices.