This class serves as a wrapper forArrays with many of the operations found in indexed sequences. Where needed, instances of arrays are implicitly converted into this class. There is generally no reason to create an instance explicitly or use anArrayOps type. It is better to work with plainArray types instead and rely on the implicit conversion toArrayOps when calling a method (which does not actually allocate an instance ofArrayOps because it is a value class).
NeitherArray norArrayOps are proper collection types (i.e. they do not extendIterable or evenIterableOnce).mutable.ArraySeq andimmutable.ArraySeq serve this purpose.
The difference between this class andArraySeqs is that calling transformer methods such asfilter andmap will yield an array, whereas anArraySeq will remain anArraySeq.
type of the elements contained in this array.
A copy of this array with an element appended.
A copy of this array with all elements of a collection appended.
A copy of this array with all elements of an array appended.
Builds a new array by applying a partial function to all elements of this array on which the function is defined.
Builds a new array by applying a partial function to all elements of this array on which the function is defined.
the element type of the returned array.
the partial function which filters and maps the array.
a new array resulting from applying the given partial functionpf to each element on which it is defined and collecting the results. The order of the elements is preserved.
Finds the first element of the array for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the array for which the given partial function is defined, and applies the partial function to it.
Iterates over combinations of elements.
Iterates over combinations of elements.
Acombination of lengthn is a sequence ofn elements selected in order of their first index in this sequence.
For example,"xyx" has two combinations of length 2. Thex is selected first:"xx","xy". The sequence"yx" is not returned as a combination because it is subsumed by"xy".
If there is more than one way to generate the same combination, only one will be returned.
For example, the result"xy" arbitrarily selected one of thex elements.
As a further illustration,"xyxx" has three different ways to generate"xy" because there are three elementsx to choose from. Moreover, there are three unordered pairs"xx" but only one is returned.
It is not specified which of these equal combinations is returned. It is an implementation detail that should not be relied on. For example, the combination"xx" does not necessarily contain the firstx in this sequence. This behavior is observable if the elements compare equal but are not identical.
As a consequence,"xyx".combinations(3).next() is"xxy": the combination does not reflect the order of the original sequence, but the order in which elements were selected, by "first index"; the order of eachx element is also arbitrary.
An Iterator which traverses the n-element combinations of this array
Array('a', 'b', 'b', 'b', 'c').combinations(2).map(runtime.ScalaRunTime.stringOf).foreach(println)// Array(a, b)// Array(a, c)// Array(b, b)// Array(b, c)Array('b', 'a', 'b').combinations(2).map(runtime.ScalaRunTime.stringOf).foreach(println)// Array(b, b)// Array(b, a)Tests whether this array contains a given value as an element.
Tests whether this array contains a given value as an element.
the element to test.
true if this array has an element that is equal (as determined by==) toelem,false otherwise.
Copy elements of this array to another array.
Copy elements of this array to another array. Fills the given arrayxs starting at index 0. Copying will stop once either all the elements of this array have been copied, or the end of the array is reached.
the type of the elements of the array.
the array to fill.
Copy elements of this array to another array.
Copy elements of this array to another array. Fills the given arrayxs starting at indexstart. Copying will stop once either all the elements of this array have been copied, or the end of the array is reached.
the type of the elements of the array.
the starting index within the destination array.
the array to fill.
Copy elements of this array to another array.
Copy elements of this array to another array. Fills the given arrayxs starting at indexstart with at mostlen values. Copying will stop once either all the elements of this array have been copied, or the end of the array is reached, orlen elements have been copied.
the type of the elements of the array.
the maximal number of elements to copy.
the starting index within the destination array.
the array to fill.
Counts the number of elements in this array which satisfy a predicate
Counts the number of elements in this array which satisfy a predicate
Computes the multiset difference between this array and another sequence.
Computes the multiset difference between this array and another sequence.
the sequence of elements to remove
a new array which contains all elements of this array except some of occurrences of elements that also appear inthat. If an element valuex appearsn times inthat, then the firstn occurrences ofx will not form part of the result, but any following occurrences will.
Selects all the elements of this array ignoring the duplicates.
Selects all the elements of this array ignoring the duplicates.
a new array consisting of all the elements of this array without duplicates.
Selects all the elements of this array ignoring the duplicates as determined by== after applying the transforming functionf.
Selects all the elements of this array ignoring the duplicates as determined by== after applying the transforming functionf.
the type of the elements after being transformed byf
The transforming function whose result is used to determine the uniqueness of each element
a new array consisting of all the elements of this array without duplicates.
The rest of the array without itsn first elements.
The rest of the array without itsn last elements.
Drops longest prefix of elements that satisfy a predicate.
Drops longest prefix of elements that satisfy a predicate.
The predicate used to test elements.
the longest suffix of this array whose first element does not satisfy the predicatep.
Tests whether this array ends with the given array.
Tests whether this array ends with the given array.
the array to test
true if this array hasthat as a suffix,false otherwise.
Tests whether this array ends with the given sequence.
Tests whether this array ends with the given sequence.
the sequence to test
true if this array hasthat as a suffix,false otherwise.
Tests whether a predicate holds for at least one element of this array.
Tests whether a predicate holds for at least one element of this array.
the predicate used to test elements.
true if the given predicatep is satisfied by at least one element of this array, otherwisefalse
Selects all elements of this array which satisfy a predicate.
Selects all elements of this array which satisfy a predicate.
the predicate used to test elements.
a new array consisting of all elements of this array that satisfy the given predicatep.
Selects all elements of this array which do not satisfy a predicate.
Selects all elements of this array which do not satisfy a predicate.
the predicate used to test elements.
a new array consisting of all elements of this array that do not satisfy the given predicatep.
Finds the first element of the array satisfying a predicate, if any.
Finds the first element of the array satisfying a predicate, if any.
the predicate used to test elements.
an option value containing the first element in the array that satisfiesp, orNone if none exists.
Builds a new array by applying a function to all elements of this array and using the elements of the resulting collections.
Builds a new array by applying a function to all elements of this array and using the elements of the resulting collections.
the element type of the returned array.
the function to apply to each element.
a new array resulting from applying the given collection-valued functionf to each element of this array and concatenating the results.
Flattens a two-dimensional array by concatenating all its rows into a single array.
Flattens a two-dimensional array by concatenating all its rows into a single array.
Type of row elements.
A function that converts elements of this array to rows - Iterables of typeB.
An array obtained by concatenating rows of this array.
Folds the elements of this array using the specified associative binary operator.
Folds the elements of this array using the specified associative binary operator.
a type parameter for the binary operator, a supertype ofA.
a binary operator that must be associative.
a neutral element for the fold operation; may be added to the result an arbitrary number of times, and must not change the result (e.g.,Nil for list concatenation, 0 for addition, or 1 for multiplication).
the result of applying the fold operatorop between all the elements, orz if this array is empty.
Applies a binary operator to a start value and all elements of this array, going left to right.
Applies a binary operator to a start value and all elements of this array, going left to right.
the result type of the binary operator.
the binary operator.
the start value.
the result of insertingop between consecutive elements of this array, going left to right with the start valuez on the left:
op(...op(z, x_1), x_2, ..., x_n) wherex1, ..., xn are the elements of this array. Returnsz if this array is empty.
Applies a binary operator to all elements of this array and a start value, going right to left.
Applies a binary operator to all elements of this array and a start value, going right to left.
the result type of the binary operator.
the binary operator.
the start value.
the result of insertingop between consecutive elements of this array, going right to left with the start valuez on the right:
op(x_1, op(x_2, ... op(x_n, z)...)) wherex1, ..., xn are the elements of this array. Returnsz if this array is empty.
Tests whether a predicate holds for all elements of this array.
Tests whether a predicate holds for all elements of this array.
the predicate used to test elements.
true if this array is empty or the given predicatep holds for all elements of this array, otherwisefalse.
Applyf to each element for its side effects.
Applyf to each element for its side effects. Note: [U] parameter needed to help scalac's type inference.
Partitions this array into a map of arrays according to some discriminator function.
Partitions this array into a map of arrays according to some discriminator function.
the type of keys returned by the discriminator function.
the discriminator function.
A map from keys to arrays such that the following invariant holds:
(xs groupBy f)(k) = xs filter (x => f(x) == k) That is, every keyk is bound to an array of those elementsx for whichf(x) equalsk.
Partitions this array into a map of arrays according to a discriminator functionkey.
Partitions this array into a map of arrays according to a discriminator functionkey. Each element in a group is transformed into a value of typeB using thevalue function.
It is equivalent togroupBy(key).mapValues(_.map(f)), but more efficient.
case class User(name: String, age: Int)def namesByAge(users: Array[User]): Map[Int, Array[String]] = users.groupMap(_.age)(_.name)the type of values returned by the transformation function
the type of keys returned by the discriminator function
the element transformation function
the discriminator function
Partitions elements in fixed size arrays.
Partitions elements in fixed size arrays.
the number of elements per group
An iterator producing arrays of sizesize, except the last will be less than sizesize if the elements don't divide evenly.
scala.collection.Iterator, methodgrouped
Selects the first element of this array.
Selects the first element of this array.
the first element of this array.
NoSuchElementExceptionif the array is empty.
Optionally selects the first element.
Optionally selects the first element.
the first element of this array if it is nonempty,None if it is empty.
Finds index of first occurrence of some value in this array after or at some start index.
Finds index of first occurrence of some value in this array after or at some start index.
the element value to search for.
the start index
the index>= from of the first element of this array that is equal (as determined by==) toelem, or-1, if none exists.
Finds index of the first element satisfying some predicate after or at some start index.
Finds index of the first element satisfying some predicate after or at some start index.
the start index
the predicate used to test elements.
the index>= from of the first element of this array that satisfies the predicatep, or-1, if none exists.
Produces the range of all indices of this sequence.
Produces the range of all indices of this sequence.
aRange value from0 to one less than the length of this array.
The initial part of the array without its last element.
Iterates over the inits of this array.
Iterates over the inits of this array. The first value will be this array and the final one will be an empty array, with the intervening values the results of successive applications ofinit.
an iterator over all the inits of this array
Computes the multiset intersection between this array and another sequence.
Computes the multiset intersection between this array and another sequence.
the sequence of elements to intersect with.
a new array which contains all elements of this array which also appear inthat. If an element valuex appearsn times inthat, then the firstn occurrences ofx will be retained in the result, but any following occurrences will be omitted.
Tests whether the array is empty.
Tests whether the array is empty.
true if the array contains no elements,false otherwise.
The size of this array.
Selects the last element.
Selects the last element.
The last element of this array.
NoSuchElementExceptionIf the array is empty.
Finds index of last occurrence of some value in this array before or at a given end index.
Finds index of last occurrence of some value in this array before or at a given end index.
the element value to search for.
the end index.
the index<= end of the last element of this array that is equal (as determined by==) toelem, or-1, if none exists.
Finds index of last element satisfying some predicate before or at given end index.
Finds index of last element satisfying some predicate before or at given end index.
the predicate used to test elements.
the index<= end of the last element of this array that satisfies the predicatep, or-1, if none exists.
Optionally selects the last element.
Optionally selects the last element.
the last element of this array$ if it is nonempty,None if it is empty.
Analogous tozip except that the elements in each collection are not consumed until a strict operation is invoked on the returnedLazyZip2 decorator.
Analogous tozip except that the elements in each collection are not consumed until a strict operation is invoked on the returnedLazyZip2 decorator.
Calls tolazyZip can be chained to support higher arities (up to 4) without incurring the expense of constructing and deconstructing intermediary tuples.
val xs = List(1, 2, 3)val res = (xs lazyZip xs lazyZip xs lazyZip xs).map((a, b, c, d) => a + b + c + d)// res == List(4, 8, 12)the type of the second element in each eventual pair
the iterable providing the second element of each eventual pair
a decoratorLazyZip2 that allows strict operations to be performed on the lazily evaluated pairs or chained calls tolazyZip. Implicit conversion toIterable[(A, B)] is also supported.
Compares the length of this array to a test value.
Compares the length of this array to a test value.
the test value that gets compared with the length.
A valuex where
x < 0 if this.length < lenx == 0 if this.length == lenx > 0 if this.length > lenMethod mirroringSeqOps.lengthIs for consistency, except it returns anInt becauselength is known and comparison is constant-time.
Method mirroringSeqOps.lengthIs for consistency, except it returns anInt becauselength is known and comparison is constant-time.
These operations are equivalent tolengthCompare(Int), and allow the following more readable usages:
this.lengthIs < len // this.lengthCompare(len) < 0this.lengthIs <= len // this.lengthCompare(len) <= 0this.lengthIs == len // this.lengthCompare(len) == 0this.lengthIs != len // this.lengthCompare(len) != 0this.lengthIs >= len // this.lengthCompare(len) >= 0this.lengthIs > len // this.lengthCompare(len) > 0Builds a new array by applying a function to all elements of this array.
Builds a new array by applying a function to all elements of this array.
the element type of the returned array.
the function to apply to each element.
a new array resulting from applying the given functionf to each element of this array and collecting the results.
Tests whether the array is not empty.
Tests whether the array is not empty.
true if the array contains at least one element,false otherwise.
A copy of this array with an element value appended until a given target length is reached.
A copy of this array with an element value appended until a given target length is reached.
the element type of the returned array.
the padding value
the target length
a new array consisting of all elements of this array followed by the minimal number of occurrences ofelem so that the resulting collection has a length of at leastlen.
A pair of, first, all elements that satisfy predicatep and, second, all elements that do not.
A pair of, first, all elements that satisfy predicatep and, second, all elements that do not.
Applies a functionf to each element of the array and returns a pair of arrays: the first one made of those values returned byf that were wrapped inscala.util.Left, and the second one made of those wrapped inscala.util.Right.
Applies a functionf to each element of the array and returns a pair of arrays: the first one made of those values returned byf that were wrapped inscala.util.Left, and the second one made of those wrapped inscala.util.Right.
Example:
val xs = Array(1, "one", 2, "two", 3, "three") partitionMap { case i: Int => Left(i) case s: String => Right(s)}// xs == (Array(1, 2, 3),// Array(one, two, three))the element type of the first resulting collection
the element type of the second resulting collection
the 'split function' mapping the elements of this array to anscala.util.Either
a pair of arrays: the first one made of those values returned byf that were wrapped inscala.util.Left, and the second one made of those wrapped inscala.util.Right.
Returns a copy of this array with patched values.
Returns a copy of this array with patched values. Patching at negative indices is the same as patching starting at 0. Patching at indices at or larger than the length of the original array appends the patch to the end. If more values are replaced than actually exist, the excess is ignored.
The start index from which to patch
The patch values
The number of values in the original array that are replaced by the patch.
Iterates over distinct permutations of elements.
Iterates over distinct permutations of elements.
An Iterator which traverses the distinct permutations of this array.
Array('a', 'b', 'b').permutations.map(runtime.ScalaRunTime.stringOf).foreach(println)// Array(a, b, b)// Array(b, a, b)// Array(b, b, a)A copy of this array with an element prepended.
A copy of this array with all elements of a collection prepended.
A copy of this array with all elements of an array prepended.
Returns a new array with the elements in reversed order.
An iterator yielding elements in reversed order.
An iterator yielding elements in reversed order.
Note:xs.reverseIterator is the same asxs.reverse.iterator but implemented more efficiently.
an iterator yielding the elements of this array in reversed order
Computes a prefix scan of the elements of the array.
Computes a prefix scan of the elements of the array.
Note: The neutral elementz may be applied more than once.
element type of the resulting array
the associative operator for the scan
neutral element for the operatorop
a new array containing the prefix scan of the elements in this array
Produces an array containing cumulative results of applying the binary operator going left to right.
Produces an array containing cumulative results of applying the binary operator going left to right.
the result type of the binary operator.
the binary operator.
the start value.
array with intermediate values. Example:
Array(1, 2, 3, 4).scanLeft(0)(_ + _) == Array(0, 1, 3, 6, 10)Produces an array containing cumulative results of applying the binary operator going right to left.
Produces an array containing cumulative results of applying the binary operator going right to left.
the result type of the binary operator.
the binary operator.
the start value.
array with intermediate values. Example:
Array(4, 3, 2, 1).scanRight(0)(_ + _) == Array(10, 6, 3, 1, 0)The size of this array.
Compares the size of this array to a test value.
Compares the size of this array to a test value.
the test value that gets compared with the size.
A valuex where
x < 0 if this.size < otherSizex == 0 if this.size == otherSizex > 0 if this.size > otherSizeMethod mirroringSeqOps.sizeIs for consistency, except it returns anInt becausesize is known and comparison is constant-time.
Method mirroringSeqOps.sizeIs for consistency, except it returns anInt becausesize is known and comparison is constant-time.
These operations are equivalent tosizeCompare(Int), and allow the following more readable usages:
this.sizeIs < size // this.sizeCompare(size) < 0this.sizeIs <= size // this.sizeCompare(size) <= 0this.sizeIs == size // this.sizeCompare(size) == 0this.sizeIs != size // this.sizeCompare(size) != 0this.sizeIs >= size // this.sizeCompare(size) >= 0this.sizeIs > size // this.sizeCompare(size) > 0Selects an interval of elements.
Selects an interval of elements. The returned array is made up of all elementsx which satisfy the invariant:
from <= indexOf(x) < untilthe lowest index to include from this array.
the lowest index to EXCLUDE from this array.
an array containing the elements greater than or equal to indexfrom extending up to (but not including) indexuntil of this array.
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)
the number of elements per group
the distance between the first elements of successive groups
An iterator producing arrays of sizesize, except the last element (which may be the only element) will be truncated if there are fewer thansize elements remaining to be grouped.
scala.collection.Iterator, methodsliding
Sorts this array according to the Ordering which results from transforming an implicitly given Ordering with a transformation function.
Sorts this array according to the Ordering which results from transforming an implicitly given Ordering with a transformation function.
the target type of the transformationf, and the type where the orderingord is defined.
the transformation function mapping elements to some other domainB.
the ordering assumed on domainB.
an array consisting of the elements of this array sorted according to the ordering wherex < y iford.lt(f(x), f(y)).
Sorts this array according to a comparison function.
Sorts this array according to a comparison function.
The sort is stable. That is, elements that are equal (as determined bylt) appear in the same order in the sorted sequence as in the original.
the comparison function which tests whether its first argument precedes its second argument in the desired ordering.
an array consisting of the elements of this array sorted according to the comparison functionlt.
Sorts this array according to an Ordering.
Sorts this array according to an Ordering.
The sort is stable. That is, elements that are equal (as determined bylt) appear in the same order in the sorted sequence as in the original.
the ordering to be used to compare elements.
an array consisting of the elements of this array sorted according to the orderingord.
Splits this array into a prefix/suffix pair according to a predicate.
Splits this array into a prefix/suffix pair according to a predicate.
Note:c span p is equivalent to (but more efficient than)(c takeWhile p, c dropWhile p), provided the evaluation of the predicatep does not cause any side-effects.
the test predicate
a pair consisting of the longest prefix of this array whose elements all satisfyp, and the rest of this array.
Splits this array into two at a given position.
Splits this array into two at a given position. Note:c splitAt n is equivalent to(c take n, c drop n).
the position at which to split.
a pair of arrays consisting of the firstn elements of this array, and the other elements.
Tests whether this array starts with the given array.
Tests whether this array contains the given array at a given index.
Tests whether this array contains the given array at a given index.
the index where the array is searched.
the array to test
true if the arraythat is contained in this array at indexoffset, otherwisefalse.
Tests whether this array contains the given sequence at a given index.
Tests whether this array contains the given sequence at a given index.
the index where the sequence is searched.
the sequence to test
true if the sequencethat is contained in this array at indexoffset, otherwisefalse.
The rest of the array without its first element.
Iterates over the tails of this array.
Iterates over the tails of this array. The first value will be this array and the final one will be an empty array, with the intervening values the results of successive applications oftail.
an iterator over all the tails of this array
An array containing the firstn elements of this array.
An array containing the lastn elements of this array.
Takes longest prefix of elements that satisfy a predicate.
Takes longest prefix of elements that satisfy a predicate.
The predicate used to test elements.
the longest prefix of this array whose elements all satisfy the predicatep.
Create a copy of this array with the specified element type.
Transposes a two dimensional array.
Transposes a two dimensional array.
Type of row elements.
A function that converts elements of this array to rows - arrays of typeB.
An array obtained by replacing elements of this arrays with rows the represent.
Converts an array of pairs into an array of first elements and an array of second elements.
Converts an array of pairs into an array of first elements and an array of second elements.
the type of the first half of the element pairs
the type of the second half of the element pairs
an implicit conversion which asserts that the element type of this Array is a pair.
a class tag forA1 type parameter that is required to create an instance ofArray[A1]
a class tag forA2 type parameter that is required to create an instance ofArray[A2]
a pair of Arrays, containing, respectively, the first and second half of each element pair of this Array.
Converts an array of triples into three arrays, one containing the elements from each position of the triple.
Converts an array of triples into three arrays, one containing the elements from each position of the triple.
the type of the first of three elements in the triple
the type of the second of three elements in the triple
the type of the third of three elements in the triple
an implicit conversion which asserts that the element type of this Array is a triple.
a class tag for T1 type parameter that is required to create an instance of Array[T1]
a class tag for T2 type parameter that is required to create an instance of Array[T2]
a class tag for T3 type parameter that is required to create an instance of Array[T3]
a triple of Arrays, containing, respectively, the first, second, and third elements from each element triple of this Array.
A copy of this array with one single replaced element.
A copy of this array with one single replaced element.
the replacing element
the position of the replacement
a new array which is a copy of this array with the element at positionindex replaced byelem.
IndexOutOfBoundsExceptionifindex does not satisfy0 <= index < length.
Creates a non-strict filter of this array.
Creates a non-strict filter of this array.
Note: the difference betweenc filter p andc withFilter p is that the former creates a new array, whereas the latter only restricts the domain of subsequentmap,flatMap,foreach, andwithFilter operations.
the predicate used to test elements.
an object of classArrayOps.WithFilter, which supportsmap,flatMap,foreach, andwithFilter operations. All these operations apply to those elements of this array which satisfy the predicatep.
Returns an array formed from this array and another iterable collection by combining corresponding elements in pairs.
Returns an array formed from this array and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.
the type of the second half of the returned pairs
The iterable providing the second half of each result pair
a new array containing pairs consisting of corresponding elements of this array andthat. The length of the returned array is the minimum of the lengths of this array andthat.
Returns an array formed from this array and another iterable collection by combining corresponding elements in pairs.
Returns an array formed from this array and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.
the iterable providing the second half of each result pair
the element to be used to fill up the result ifthat is shorter than this array.
the element to be used to fill up the result if this array is shorter thanthat.
a new array containing pairs consisting of corresponding elements of this array andthat. The length of the returned array is the maximum of the lengths of this array andthat. If this array is shorter thanthat,thisElem values are used to pad the result. Ifthat is shorter than this array,thatElem values are used to pad the result.
Zips this array with its indices.
Zips this array with its indices.
A new array containing pairs consisting of all elements of this array paired with their index. Indices start at0.