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<h2>Scala mode</h2> |
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/* __ *\ |
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** ________ ___ / / ___ Scala API ** |
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** / __/ __// _ | / / / _ | (c) 2003-2011, LAMP/EPFL ** |
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** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ ** |
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** /____/\___/_/ |_/____/_/ | | ** |
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** |/ ** |
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\* */ |
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package scala.collection |
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import generic._ |
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import mutable.{ Builder, ListBuffer } |
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import annotation.{tailrec, migration, bridge} |
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import annotation.unchecked.{ uncheckedVariance => uV } |
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import parallel.ParIterable |
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|
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/** A template trait for traversable collections of type `Traversable[A]`. |
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* |
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* $traversableInfo |
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* @define mutability |
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* @define traversableInfo |
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* This is a base trait of all kinds of $mutability Scala collections. It |
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* implements the behavior common to all collections, in terms of a method |
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* `foreach` with signature: |
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* {{{ |
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* def foreach[U](f: Elem => U): Unit |
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* }}} |
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* Collection classes mixing in this trait provide a concrete |
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* `foreach` method which traverses all the |
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* elements contained in the collection, applying a given function to each. |
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* They also need to provide a method `newBuilder` |
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* which creates a builder for collections of the same kind. |
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* |
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* A traversable class might or might not have two properties: strictness |
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* and orderedness. Neither is represented as a type. |
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* |
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* The instances of a strict collection class have all their elements |
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* computed before they can be used as values. By contrast, instances of |
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* a non-strict collection class may defer computation of some of their |
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* elements until after the instance is available as a value. |
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* A typical example of a non-strict collection class is a |
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* <a href="../immutable/Stream.html" target="ContentFrame"> |
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* `scala.collection.immutable.Stream`</a>. |
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* A more general class of examples are `TraversableViews`. |
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* |
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* If a collection is an instance of an ordered collection class, traversing |
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* its elements with `foreach` will always visit elements in the |
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* same order, even for different runs of the program. If the class is not |
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* ordered, `foreach` can visit elements in different orders for |
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* different runs (but it will keep the same order in the same run).' |
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* |
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* A typical example of a collection class which is not ordered is a |
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* `HashMap` of objects. The traversal order for hash maps will |
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* depend on the hash codes of its elements, and these hash codes might |
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* differ from one run to the next. By contrast, a `LinkedHashMap` |
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* is ordered because it's `foreach` method visits elements in the |
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* order they were inserted into the `HashMap`. |
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* |
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* @author Martin Odersky |
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* @version 2.8 |
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* @since 2.8 |
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* @tparam A the element type of the collection |
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* @tparam Repr the type of the actual collection containing the elements. |
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* |
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* @define Coll Traversable |
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* @define coll traversable collection |
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*/ |
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trait TraversableLike[+A, +Repr] extends HasNewBuilder[A, Repr] |
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with FilterMonadic[A, Repr] |
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with TraversableOnce[A] |
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with GenTraversableLike[A, Repr] |
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with Parallelizable[A, ParIterable[A]] |
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{ |
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self => |
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import Traversable.breaks._ |
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/** The type implementing this traversable */ |
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protected type Self = Repr |
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/** The collection of type $coll underlying this `TraversableLike` object. |
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* By default this is implemented as the `TraversableLike` object itself, |
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* but this can be overridden. |
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*/ |
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def repr: Repr = this.asInstanceOf[Repr] |
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/** The underlying collection seen as an instance of `$Coll`. |
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* By default this is implemented as the current collection object itself, |
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* but this can be overridden. |
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*/ |
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protected[this] def thisCollection: Traversable[A] = this.asInstanceOf[Traversable[A]] |
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/** A conversion from collections of type `Repr` to `$Coll` objects. |
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* By default this is implemented as just a cast, but this can be overridden. |
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*/ |
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protected[this] def toCollection(repr: Repr): Traversable[A] = repr.asInstanceOf[Traversable[A]] |
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/** Creates a new builder for this collection type. |
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*/ |
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protected[this] def newBuilder: Builder[A, Repr] |
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protected[this] def parCombiner = ParIterable.newCombiner[A] |
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/** Applies a function `f` to all elements of this $coll. |
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* |
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* Note: this method underlies the implementation of most other bulk operations. |
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* It's important to implement this method in an efficient way. |
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* |
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* |
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* @param f the function that is applied for its side-effect to every element. |
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* The result of function `f` is discarded. |
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* |
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* @tparam U the type parameter describing the result of function `f`. |
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* This result will always be ignored. Typically `U` is `Unit`, |
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* but this is not necessary. |
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* |
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* @usecase def foreach(f: A => Unit): Unit |
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*/ |
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def foreach[U](f: A => U): Unit |
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/** Tests whether this $coll is empty. |
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* |
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* @return `true` if the $coll contain no elements, `false` otherwise. |
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*/ |
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def isEmpty: Boolean = { |
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var result = true |
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breakable { |
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for (x <- this) { |
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result = false |
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break |
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} |
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} |
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result |
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} |
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/** Tests whether this $coll is known to have a finite size. |
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* All strict collections are known to have finite size. For a non-strict collection |
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* such as `Stream`, the predicate returns `true` if all elements have been computed. |
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* It returns `false` if the stream is not yet evaluated to the end. |
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* |
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* Note: many collection methods will not work on collections of infinite sizes. |
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* |
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* @return `true` if this collection is known to have finite size, `false` otherwise. |
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*/ |
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def hasDefiniteSize = true |
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def ++[B >: A, That](that: GenTraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
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val b = bf(repr) |
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if (that.isInstanceOf[IndexedSeqLike[_, _]]) b.sizeHint(this, that.seq.size) |
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b ++= thisCollection |
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b ++= that.seq |
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b.result |
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} |
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@bridge |
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def ++[B >: A, That](that: TraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = |
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++(that: GenTraversableOnce[B])(bf) |
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/** Concatenates this $coll with the elements of a traversable collection. |
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* It differs from ++ in that the right operand determines the type of the |
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* resulting collection rather than the left one. |
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* |
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* @param that the traversable to append. |
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* @tparam B the element type of the returned collection. |
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* @tparam That $thatinfo |
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* @param bf $bfinfo |
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* @return a new collection of type `That` which contains all elements |
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* of this $coll followed by all elements of `that`. |
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* |
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* @usecase def ++:[B](that: TraversableOnce[B]): $Coll[B] |
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* |
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* @return a new $coll which contains all elements of this $coll |
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* followed by all elements of `that`. |
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*/ |
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def ++:[B >: A, That](that: TraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
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val b = bf(repr) |
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if (that.isInstanceOf[IndexedSeqLike[_, _]]) b.sizeHint(this, that.size) |
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b ++= that |
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b ++= thisCollection |
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b.result |
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} |
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/** This overload exists because: for the implementation of ++: we should reuse |
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* that of ++ because many collections override it with more efficient versions. |
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* Since TraversableOnce has no '++' method, we have to implement that directly, |
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* but Traversable and down can use the overload. |
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*/ |
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def ++:[B >: A, That](that: Traversable[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = |
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(that ++ seq)(breakOut) |
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def map[B, That](f: A => B)(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
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val b = bf(repr) |
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b.sizeHint(this) |
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for (x <- this) b += f(x) |
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b.result |
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} |
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def flatMap[B, That](f: A => GenTraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
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val b = bf(repr) |
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for (x <- this) b ++= f(x).seq |
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b.result |
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} |
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/** Selects all elements of this $coll which satisfy a predicate. |
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* |
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* @param p the predicate used to test elements. |
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* @return a new $coll consisting of all elements of this $coll that satisfy the given |
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* predicate `p`. The order of the elements is preserved. |
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*/ |
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def filter(p: A => Boolean): Repr = { |
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val b = newBuilder |
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for (x <- this) |
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if (p(x)) b += x |
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b.result |
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} |
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/** Selects all elements of this $coll which do not satisfy a predicate. |
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* |
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* @param p the predicate used to test elements. |
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* @return a new $coll consisting of all elements of this $coll that do not satisfy the given |
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* predicate `p`. The order of the elements is preserved. |
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*/ |
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def filterNot(p: A => Boolean): Repr = filter(!p(_)) |
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def collect[B, That](pf: PartialFunction[A, B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
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val b = bf(repr) |
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for (x <- this) if (pf.isDefinedAt(x)) b += pf(x) |
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b.result |
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} |
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/** Builds a new collection by applying an option-valued function to all |
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* elements of this $coll on which the function is defined. |
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* |
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* @param f the option-valued function which filters and maps the $coll. |
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* @tparam B the element type of the returned collection. |
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* @tparam That $thatinfo |
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* @param bf $bfinfo |
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* @return a new collection of type `That` resulting from applying the option-valued function |
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* `f` to each element and collecting all defined results. |
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* The order of the elements is preserved. |
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* |
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* @usecase def filterMap[B](f: A => Option[B]): $Coll[B] |
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* |
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* @param pf the partial function which filters and maps the $coll. |
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* @return a new $coll resulting from applying the given option-valued function |
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* `f` to each element and collecting all defined results. |
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* The order of the elements is preserved. |
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def filterMap[B, That](f: A => Option[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
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val b = bf(repr) |
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for (x <- this) |
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f(x) match { |
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case Some(y) => b += y |
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case _ => |
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} |
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b.result |
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} |
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*/ |
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/** Partitions this $coll in two ${coll}s according to a predicate. |
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* |
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* @param p the predicate on which to partition. |
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* @return a pair of ${coll}s: the first $coll consists of all elements that |
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* satisfy the predicate `p` and the second $coll consists of all elements |
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* that don't. The relative order of the elements in the resulting ${coll}s |
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* is the same as in the original $coll. |
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*/ |
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def partition(p: A => Boolean): (Repr, Repr) = { |
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val l, r = newBuilder |
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for (x <- this) (if (p(x)) l else r) += x |
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(l.result, r.result) |
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} |
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def groupBy[K](f: A => K): immutable.Map[K, Repr] = { |
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val m = mutable.Map.empty[K, Builder[A, Repr]] |
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for (elem <- this) { |
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val key = f(elem) |
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val bldr = m.getOrElseUpdate(key, newBuilder) |
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bldr += elem |
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} |
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val b = immutable.Map.newBuilder[K, Repr] |
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for ((k, v) <- m) |
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b += ((k, v.result)) |
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b.result |
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} |
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/** Tests whether a predicate holds for all elements of this $coll. |
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* |
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* $mayNotTerminateInf |
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* |
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* @param p the predicate used to test elements. |
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* @return `true` if the given predicate `p` holds for all elements |
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* of this $coll, otherwise `false`. |
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*/ |
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def forall(p: A => Boolean): Boolean = { |
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var result = true |
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breakable { |
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for (x <- this) |
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if (!p(x)) { result = false; break } |
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} |
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result |
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} |
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/** Tests whether a predicate holds for some of the elements of this $coll. |
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* |
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* $mayNotTerminateInf |
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* |
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* @param p the predicate used to test elements. |
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* @return `true` if the given predicate `p` holds for some of the |
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* elements of this $coll, otherwise `false`. |
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*/ |
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def exists(p: A => Boolean): Boolean = { |
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var result = false |
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breakable { |
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for (x <- this) |
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if (p(x)) { result = true; break } |
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} |
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result |
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} |
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/** Finds the first element of the $coll satisfying a predicate, if any. |
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* |
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* $mayNotTerminateInf |
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* $orderDependent |
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* |
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* @param p the predicate used to test elements. |
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* @return an option value containing the first element in the $coll |
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* that satisfies `p`, or `None` if none exists. |
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*/ |
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def find(p: A => Boolean): Option[A] = { |
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var result: Option[A] = None |
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breakable { |
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for (x <- this) |
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if (p(x)) { result = Some(x); break } |
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} |
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result |
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} |
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def scan[B >: A, That](z: B)(op: (B, B) => B)(implicit cbf: CanBuildFrom[Repr, B, That]): That = scanLeft(z)(op) |
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def scanLeft[B, That](z: B)(op: (B, A) => B)(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
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val b = bf(repr) |
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b.sizeHint(this, 1) |
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var acc = z |
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b += acc |
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for (x <- this) { acc = op(acc, x); b += acc } |
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b.result |
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} |
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@migration(2, 9, |
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"This scanRight definition has changed in 2.9.\n" + |
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"The previous behavior can be reproduced with scanRight.reverse." |
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) |
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def scanRight[B, That](z: B)(op: (A, B) => B)(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
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var scanned = List(z) |
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var acc = z |
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for (x <- reversed) { |
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acc = op(x, acc) |
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scanned ::= acc |
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} |
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val b = bf(repr) |
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for (elem <- scanned) b += elem |
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b.result |
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} |
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/** Selects the first element of this $coll. |
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* $orderDependent |
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* @return the first element of this $coll. |
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* @throws `NoSuchElementException` if the $coll is empty. |
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*/ |
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def head: A = { |
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var result: () => A = () => throw new NoSuchElementException |
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breakable { |
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for (x <- this) { |
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result = () => x |
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break |
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} |
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} |
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result() |
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} |
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/** Optionally selects the first element. |
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* $orderDependent |
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* @return the first element of this $coll if it is nonempty, `None` if it is empty. |
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*/ |
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def headOption: Option[A] = if (isEmpty) None else Some(head) |
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/** Selects all elements except the first. |
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* $orderDependent |
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* @return a $coll consisting of all elements of this $coll |
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* except the first one. |
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* @throws `UnsupportedOperationException` if the $coll is empty. |
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*/ |
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override def tail: Repr = { |
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if (isEmpty) throw new UnsupportedOperationException("empty.tail") |
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drop(1) |
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} |
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/** Selects the last element. |
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* $orderDependent |
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* @return The last element of this $coll. |
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* @throws NoSuchElementException If the $coll is empty. |
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*/ |
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def last: A = { |
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var lst = head |
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for (x <- this) |
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lst = x |
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lst |
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} |
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/** Optionally selects the last element. |
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* $orderDependent |
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* @return the last element of this $coll$ if it is nonempty, `None` if it is empty. |
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*/ |
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def lastOption: Option[A] = if (isEmpty) None else Some(last) |
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/** Selects all elements except the last. |
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* $orderDependent |
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* @return a $coll consisting of all elements of this $coll |
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* except the last one. |
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* @throws `UnsupportedOperationException` if the $coll is empty. |
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*/ |
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def init: Repr = { |
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if (isEmpty) throw new UnsupportedOperationException("empty.init") |
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var lst = head |
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var follow = false |
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val b = newBuilder |
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b.sizeHint(this, -1) |
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for (x <- this.seq) { |
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if (follow) b += lst |
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else follow = true |
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lst = x |
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} |
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b.result |
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} |
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def take(n: Int): Repr = slice(0, n) |
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def drop(n: Int): Repr = |
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if (n <= 0) { |
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val b = newBuilder |
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b.sizeHint(this) |
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b ++= thisCollection result |
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} |
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else sliceWithKnownDelta(n, Int.MaxValue, -n) |
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def slice(from: Int, until: Int): Repr = sliceWithKnownBound(math.max(from, 0), until) |
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// Precondition: from >= 0, until > 0, builder already configured for building. |
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private[this] def sliceInternal(from: Int, until: Int, b: Builder[A, Repr]): Repr = { |
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var i = 0 |
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breakable { |
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for (x <- this.seq) { |
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if (i >= from) b += x |
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i += 1 |
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if (i >= until) break |
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} |
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} |
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b.result |
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} |
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// Precondition: from >= 0 |
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private[scala] def sliceWithKnownDelta(from: Int, until: Int, delta: Int): Repr = { |
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val b = newBuilder |
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if (until <= from) b.result |
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else { |
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b.sizeHint(this, delta) |
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sliceInternal(from, until, b) |
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} |
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} |
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// Precondition: from >= 0 |
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private[scala] def sliceWithKnownBound(from: Int, until: Int): Repr = { |
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val b = newBuilder |
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if (until <= from) b.result |
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else { |
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b.sizeHintBounded(until - from, this) |
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sliceInternal(from, until, b) |
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} |
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} |
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def takeWhile(p: A => Boolean): Repr = { |
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val b = newBuilder |
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breakable { |
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for (x <- this) { |
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if (!p(x)) break |
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b += x |
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} |
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} |
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b.result |
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} |
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def dropWhile(p: A => Boolean): Repr = { |
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val b = newBuilder |
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var go = false |
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for (x <- this) { |
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if (!p(x)) go = true |
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if (go) b += x |
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} |
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b.result |
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} |
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def span(p: A => Boolean): (Repr, Repr) = { |
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val l, r = newBuilder |
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var toLeft = true |
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for (x <- this) { |
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toLeft = toLeft && p(x) |
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(if (toLeft) l else r) += x |
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} |
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(l.result, r.result) |
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} |
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|
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def splitAt(n: Int): (Repr, Repr) = { |
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val l, r = newBuilder |
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l.sizeHintBounded(n, this) |
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if (n >= 0) r.sizeHint(this, -n) |
|
var i = 0 |
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for (x <- this) { |
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(if (i < n) l else r) += x |
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i += 1 |
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} |
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(l.result, r.result) |
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} |
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|
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/** Iterates over the tails of this $coll. The first value will be this |
|
* $coll and the final one will be an empty $coll, with the intervening |
|
* values the results of successive applications of `tail`. |
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* |
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* @return an iterator over all the tails of this $coll |
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* @example `List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)` |
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*/ |
|
def tails: Iterator[Repr] = iterateUntilEmpty(_.tail) |
|
|
|
/** Iterates over the inits of this $coll. The first value will be this |
|
* $coll and the final one will be an empty $coll, with the intervening |
|
* values the results of successive applications of `init`. |
|
* |
|
* @return an iterator over all the inits of this $coll |
|
* @example `List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)` |
|
*/ |
|
def inits: Iterator[Repr] = iterateUntilEmpty(_.init) |
|
|
|
/** Copies elements of this $coll to an array. |
|
* Fills the given array `xs` with at most `len` elements of |
|
* this $coll, starting at position `start`. |
|
* Copying will stop once either the end of the current $coll is reached, |
|
* or the end of the array is reached, or `len` elements have been copied. |
|
* |
|
* $willNotTerminateInf |
|
* |
|
* @param xs the array to fill. |
|
* @param start the starting index. |
|
* @param len the maximal number of elements to copy. |
|
* @tparam B the type of the elements of the array. |
|
* |
|
* |
|
* @usecase def copyToArray(xs: Array[A], start: Int, len: Int): Unit |
|
*/ |
|
def copyToArray[B >: A](xs: Array[B], start: Int, len: Int) { |
|
var i = start |
|
val end = (start + len) min xs.length |
|
breakable { |
|
for (x <- this) { |
|
if (i >= end) break |
|
xs(i) = x |
|
i += 1 |
|
} |
|
} |
|
} |
|
|
|
def toTraversable: Traversable[A] = thisCollection |
|
def toIterator: Iterator[A] = toStream.iterator |
|
def toStream: Stream[A] = toBuffer.toStream |
|
|
|
/** Converts this $coll to a string. |
|
* |
|
* @return a string representation of this collection. By default this |
|
* string consists of the `stringPrefix` of this $coll, |
|
* followed by all elements separated by commas and enclosed in parentheses. |
|
*/ |
|
override def toString = mkString(stringPrefix + "(", ", ", ")") |
|
|
|
/** Defines the prefix of this object's `toString` representation. |
|
* |
|
* @return a string representation which starts the result of `toString` |
|
* applied to this $coll. By default the string prefix is the |
|
* simple name of the collection class $coll. |
|
*/ |
|
def stringPrefix : String = { |
|
var string = repr.asInstanceOf[AnyRef].getClass.getName |
|
val idx1 = string.lastIndexOf('.' : Int) |
|
if (idx1 != -1) string = string.substring(idx1 + 1) |
|
val idx2 = string.indexOf('$') |
|
if (idx2 != -1) string = string.substring(0, idx2) |
|
string |
|
} |
|
|
|
/** Creates a non-strict view of this $coll. |
|
* |
|
* @return a non-strict view of this $coll. |
|
*/ |
|
def view = new TraversableView[A, Repr] { |
|
protected lazy val underlying = self.repr |
|
override def foreach[U](f: A => U) = self foreach f |
|
} |
|
|
|
/** Creates a non-strict view of a slice of this $coll. |
|
* |
|
* Note: the difference between `view` and `slice` is that `view` produces |
|
* a view of the current $coll, whereas `slice` produces a new $coll. |
|
* |
|
* Note: `view(from, to)` is equivalent to `view.slice(from, to)` |
|
* $orderDependent |
|
* |
|
* @param from the index of the first element of the view |
|
* @param until the index of the element following the view |
|
* @return a non-strict view of a slice of this $coll, starting at index `from` |
|
* and extending up to (but not including) index `until`. |
|
*/ |
|
def view(from: Int, until: Int): TraversableView[A, Repr] = view.slice(from, until) |
|
|
|
/** Creates a non-strict filter of this $coll. |
|
* |
|
* 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. |
|
* $orderDependent |
|
* |
|
* @param p the predicate used to test elements. |
|
* @return an object of class `WithFilter`, which supports |
|
* `map`, `flatMap`, `foreach`, and `withFilter` operations. |
|
* All these operations apply to those elements of this $coll which |
|
* satisfy the predicate `p`. |
|
*/ |
|
def withFilter(p: A => Boolean): FilterMonadic[A, Repr] = new WithFilter(p) |
|
|
|
/** A class supporting filtered operations. Instances of this class are |
|
* returned by method `withFilter`. |
|
*/ |
|
class WithFilter(p: A => Boolean) extends FilterMonadic[A, Repr] { |
|
|
|
/** Builds a new collection by applying a function to all elements of the |
|
* outer $coll containing this `WithFilter` instance that satisfy predicate `p`. |
|
* |
|
* @param f the function to apply to each element. |
|
* @tparam B the element type of the returned collection. |
|
* @tparam That $thatinfo |
|
* @param bf $bfinfo |
|
* @return a new collection of type `That` resulting from applying |
|
* the given function `f` to each element of the outer $coll |
|
* that satisfies predicate `p` and collecting the results. |
|
* |
|
* @usecase def map[B](f: A => B): $Coll[B] |
|
* |
|
* @return a new $coll resulting from applying the given function |
|
* `f` to each element of the outer $coll that satisfies |
|
* predicate `p` and collecting the results. |
|
*/ |
|
def map[B, That](f: A => B)(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
|
val b = bf(repr) |
|
for (x <- self) |
|
if (p(x)) b += f(x) |
|
b.result |
|
} |
|
|
|
/** Builds a new collection by applying a function to all elements of the |
|
* outer $coll containing this `WithFilter` instance that satisfy |
|
* predicate `p` and concatenating the results. |
|
* |
|
* @param f the function to apply to each element. |
|
* @tparam B the element type of the returned collection. |
|
* @tparam That $thatinfo |
|
* @param bf $bfinfo |
|
* @return a new collection of type `That` resulting from applying |
|
* the given collection-valued function `f` to each element |
|
* of the outer $coll that satisfies predicate `p` and |
|
* concatenating the results. |
|
* |
|
* @usecase def flatMap[B](f: A => TraversableOnce[B]): $Coll[B] |
|
* |
|
* @return a new $coll resulting from applying the given collection-valued function |
|
* `f` to each element of the outer $coll that satisfies predicate `p` and concatenating the results. |
|
*/ |
|
def flatMap[B, That](f: A => GenTraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That = { |
|
val b = bf(repr) |
|
for (x <- self) |
|
if (p(x)) b ++= f(x).seq |
|
b.result |
|
} |
|
|
|
/** Applies a function `f` to all elements of the outer $coll containing |
|
* this `WithFilter` instance that satisfy predicate `p`. |
|
* |
|
* @param f the function that is applied for its side-effect to every element. |
|
* The result of function `f` is discarded. |
|
* |
|
* @tparam U the type parameter describing the result of function `f`. |
|
* This result will always be ignored. Typically `U` is `Unit`, |
|
* but this is not necessary. |
|
* |
|
* @usecase def foreach(f: A => Unit): Unit |
|
*/ |
|
def foreach[U](f: A => U): Unit = |
|
for (x <- self) |
|
if (p(x)) f(x) |
|
|
|
/** Further refines the filter for this $coll. |
|
* |
|
* @param q the predicate used to test elements. |
|
* @return an object of class `WithFilter`, which supports |
|
* `map`, `flatMap`, `foreach`, and `withFilter` operations. |
|
* All these operations apply to those elements of this $coll which |
|
* satisfy the predicate `q` in addition to the predicate `p`. |
|
*/ |
|
def withFilter(q: A => Boolean): WithFilter = |
|
new WithFilter(x => p(x) && q(x)) |
|
} |
|
|
|
// A helper for tails and inits. |
|
private def iterateUntilEmpty(f: Traversable[A @uV] => Traversable[A @uV]): Iterator[Repr] = { |
|
val it = Iterator.iterate(thisCollection)(f) takeWhile (x => !x.isEmpty) |
|
it ++ Iterator(Nil) map (newBuilder ++= _ result) |
|
} |
|
} |
|
|
|
|
|
</textarea> |
|
</form> |
|
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|
<script> |
|
var editor = CodeMirror.fromTextArea(document.getElementById("code"), { |
|
lineNumbers: true, |
|
matchBrackets: true, |
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theme: "ambiance", |
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mode: "text/x-scala" |
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}); |
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</script> |
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</article>
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