object Array extends java.io.Serializable
Utility methods for operating on arrays. For example:
val a = Array(1, 2) val b = Array.ofDim[Int](2) val c = Array.concat(a, b)
where the array objects a
, b
and c
have respectively the values
Array(1, 2)
, Array(0, 0)
and Array(1, 2, 0, 0)
.
- Source
- Array.scala
- Alphabetic
- By Inheritance
- Array
- Serializable
- AnyRef
- Any
- Hide All
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- Public
- Protected
Type Members
- final class UnapplySeqWrapper[T] extends AnyVal
Value Members
- final def !=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
- returns
true
if !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
- final def ##: Int
Equivalent to
x.hashCode
except for boxed numeric types andnull
.Equivalent to
x.hashCode
except for boxed numeric types andnull
. 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. Fornull
returns a hashcode wherenull.hashCode
throws aNullPointerException
.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
- final def ==(arg0: Any): Boolean
The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
- Definition Classes
- AnyRef → Any
- def apply(x: Unit, xs: Unit*): Array[Unit]
Creates an array of
Unit
objects - def apply(x: Double, xs: Double*): Array[Double]
Creates an array of
Double
objects - def apply(x: Float, xs: Float*): Array[Float]
Creates an array of
Float
objects - def apply(x: Long, xs: Long*): Array[Long]
Creates an array of
Long
objects - def apply(x: Int, xs: Int*): Array[Int]
Creates an array of
Int
objects - def apply(x: Char, xs: Char*): Array[Char]
Creates an array of
Char
objects - def apply(x: Short, xs: Short*): Array[Short]
Creates an array of
Short
objects - def apply(x: Byte, xs: Byte*): Array[Byte]
Creates an array of
Byte
objects - def apply(x: Boolean, xs: Boolean*): Array[Boolean]
Creates an array of
Boolean
objects - def apply[T](xs: T*)(implicit arg0: ClassTag[T]): Array[T]
Creates an array with given elements.
Creates an array with given elements.
- xs
the elements to put in the array
- returns
an array containing all elements from xs.
- final def asInstanceOf[T0]: T0
Forces the compiler to treat the receiver object as having type
T0
, even though doing so may violate type safety.Forces the compiler to treat the receiver object as having type
T0
, even though doing so may violate type safety.This method is useful when you believe you have type information the compiler doesn't, and it also isn't possible to check the type at runtime. In such situations, skipping type safety is the only option.
It is platform dependent whether
asInstanceOf
has any effect at runtime. It might do a runtime type test on the erasure ofT0
, insert a conversion (such as boxing/unboxing), fill in a default value, or do nothing at all.In particular,
asInstanceOf
is not a type test. It does **not** mean:this match { case x: T0 => x case _ => throw ClassCastException("...")
Use pattern matching or isInstanceOf for type testing instead.
Situations where
asInstanceOf
is useful:- when flow analysis fails to deduce
T0
automatically - when down-casting a type parameter or an abstract type member (which cannot be checked at runtime due to type erasure) If there is any doubt and you are able to type test instead, you should do so.
Be careful of using
asInstanceOf
whenT0
is a primitive type. WhenT0
is primitive,asInstanceOf
may insert a conversion instead of a type test. If your intent is to convert, use atoT
method (x.toChar
,x.toByte
, etc.).- returns
the receiver object.
- Definition Classes
- Any
- Exceptions thrown
ClassCastException
if the receiver is not an instance of the erasure ofT0
, if that can be checked on this platform
- when flow analysis fails to deduce
- def clone(): AnyRef
Create a copy of the receiver object.
Create a copy of the receiver object.
The default implementation of the
clone
method is platform dependent.- returns
a copy of the receiver object.
- def concat[T](xss: Array[T]*)(implicit arg0: ClassTag[T]): Array[T]
Concatenates all arrays into a single array.
Concatenates all arrays into a single array.
- xss
the given arrays
- returns
the array created from concatenating
xss
- def copy(src: AnyRef, srcPos: Int, dest: AnyRef, destPos: Int, length: Int): Unit
Copy one array to another.
Copy one array to another. Equivalent to Java's
System.arraycopy(src, srcPos, dest, destPos, length)
, except that this also works for polymorphic and boxed arrays.Note that the passed-in
dest
array will be modified by this call.- src
the source array.
- srcPos
starting position in the source array.
- dest
destination array.
- destPos
starting position in the destination array.
- length
the number of array elements to be copied.
- See also
java.lang.System#arraycopy
- def copyAs[A](original: Array[_], newLength: Int)(implicit ct: ClassTag[A]): Array[A]
Copy one array to another, truncating or padding with default values (if necessary) so the copy has the specified length.
Copy one array to another, truncating or padding with default values (if necessary) so the copy has the specified length. The new array can have a different type than the original one as long as the values are assignment-compatible. When copying between primitive and object arrays, boxing and unboxing are supported.
Equivalent to Java's
java.util.Arrays.copyOf(original, newLength, newType)
, except that this works for all combinations of primitive and object arrays in a single method.- See also
java.util.Arrays#copyOf
- def copyOf[A](original: Array[A], newLength: Int): Array[A]
Copy one array to another, truncating or padding with default values (if necessary) so the copy has the specified length.
Copy one array to another, truncating or padding with default values (if necessary) so the copy has the specified length.
Equivalent to Java's
java.util.Arrays.copyOf(original, newLength)
, except that this works for primitive and object arrays in a single method.- See also
java.util.Arrays#copyOf
- def empty[T](implicit arg0: ClassTag[T]): Array[T]
Returns an array of length 0
- val emptyBooleanArray: Array[Boolean]
- val emptyByteArray: Array[Byte]
- val emptyCharArray: Array[Char]
- val emptyDoubleArray: Array[Double]
- val emptyFloatArray: Array[Float]
- val emptyIntArray: Array[Int]
- val emptyLongArray: Array[Long]
- val emptyObjectArray: Array[AnyRef]
- val emptyShortArray: Array[Short]
- final def eq(arg0: AnyRef): Boolean
Tests whether the argument (
that
) is a reference to the receiver object (this
).Tests whether the argument (
that
) is a reference to the receiver object (this
).The
eq
method implements an equivalence relation on non-null instances ofAnyRef
, and has three additional properties:- It is consistent: for any non-null instances
x
andy
of typeAnyRef
, multiple invocations ofx.eq(y)
consistently returnstrue
or consistently returnsfalse
. - For any non-null instance
x
of typeAnyRef
,x.eq(null)
andnull.eq(x)
returnsfalse
. null.eq(null)
returnstrue
.
When overriding the
equals
orhashCode
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
).- returns
true
if the argument is a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
- def equals(xs: Array[AnyRef], ys: Array[AnyRef]): Boolean
Compare two arrays per element.
Compare two arrays per element.
A more efficient version of
xs.sameElements(ys)
.Note that arrays are invariant in Scala, but it may be sound to cast an array of arbitrary reference type to
Array[AnyRef]
. Arrays on the JVM are covariant in their element type.Array.equals(xs.asInstanceOf[Array[AnyRef]], ys.asInstanceOf[Array[AnyRef]])
- xs
an array of AnyRef
- ys
an array of AnyRef
- returns
true if corresponding elements are equal
- def equals(arg0: AnyRef): Boolean
The equality method for reference types.
- def fill[T](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: => T)(implicit arg0: ClassTag[T]): Array[Array[Array[Array[Array[T]]]]]
Returns a five-dimensional array that contains the results of some element computation a number of times.
Returns a five-dimensional array that contains the results of some element computation a number of times.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3rd dimension
- n4
the number of elements in the 4th dimension
- n5
the number of elements in the 5th dimension
- elem
the element computation
- def fill[T](n1: Int, n2: Int, n3: Int, n4: Int)(elem: => T)(implicit arg0: ClassTag[T]): Array[Array[Array[Array[T]]]]
Returns a four-dimensional array that contains the results of some element computation a number of times.
Returns a four-dimensional array that contains the results of some element computation a number of times.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3rd dimension
- n4
the number of elements in the 4th dimension
- elem
the element computation
- def fill[T](n1: Int, n2: Int, n3: Int)(elem: => T)(implicit arg0: ClassTag[T]): Array[Array[Array[T]]]
Returns a three-dimensional array that contains the results of some element computation a number of times.
Returns a three-dimensional array that contains the results of some element computation a number of times.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3rd dimension
- elem
the element computation
- def fill[T](n1: Int, n2: Int)(elem: => T)(implicit arg0: ClassTag[T]): Array[Array[T]]
Returns a two-dimensional array that contains the results of some element computation a number of times.
Returns a two-dimensional array that contains the results of some element computation a number of times.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- elem
the element computation
- def fill[T](n: Int)(elem: => T)(implicit arg0: ClassTag[T]): Array[T]
Returns an array that contains the results of some element computation a number of times.
Returns an array that contains the results of some element computation a number of times.
Note that this means that
elem
is computed a total of n times:scala> Array.fill(3){ math.random } res3: Array[Double] = Array(0.365461167592537, 1.550395944913685E-4, 0.7907242137333306)
- n
the number of elements desired
- elem
the element computation
- returns
an Array of size n, where each element contains the result of computing
elem
.
- def finalize(): Unit
Called by the garbage collector on the receiver object when there are no more references to the object.
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the
finalize
method is invoked, as well as the interaction betweenfinalize
and non-local returns and exceptions, are all platform dependent.- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable])
- Note
not specified by SLS as a member of AnyRef
- def from[A](it: IterableOnce[A])(implicit arg0: ClassTag[A]): Array[A]
Build an array from the iterable collection.
Build an array from the iterable collection.
scala> val a = Array.from(Seq(1, 5)) val a: Array[Int] = Array(1, 5) scala> val b = Array.from(Range(1, 5)) val b: Array[Int] = Array(1, 2, 3, 4)
- it
the iterable collection
- returns
an array consisting of elements of the iterable collection
- final def getClass(): Class[_ <: AnyRef]
Returns the runtime class representation of the object.
- def hashCode(): Int
The hashCode method for reference types.
- final def isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object has the same erasure as
T0
.Test whether the dynamic type of the receiver object has the same erasure as
T0
.Depending on what
T0
is, the test is done in one of the below ways:T0
is a non-parameterized class type, e.g.BigDecimal
: this method returnstrue
if the value of the receiver object is aBigDecimal
or a subtype ofBigDecimal
.T0
is a parameterized class type, e.g.List[Int]
: this method returnstrue
if the value of the receiver object is someList[X]
for anyX
. For example,List(1, 2, 3).isInstanceOf[List[String]]
will return true.T0
is some singleton typex.type
or literalx
: this method returnsthis.eq(x)
. For example,x.isInstanceOf[1]
is equivalent tox.eq(1)
T0
is an intersectionX with Y
orX & Y: this method is equivalent to
x.isInstanceOf[X] && x.isInstanceOf[Y]T0
is a unionX | Y
: this method is equivalent tox.isInstanceOf[X] || x.isInstanceOf[Y]
T0
is a type parameter or an abstract type member: this method is equivalent toisInstanceOf[U]
whereU
isT0
's upper bound,Any
ifT0
is unbounded. For example,x.isInstanceOf[A]
whereA
is an unbounded type parameter will return true for any value ofx
.
This is exactly equivalent to the type pattern
_: T0
- returns
true
if the receiver object is an instance of erasure of typeT0
;false
otherwise.
- Definition Classes
- Any
- Note
due to the unexpectedness of
List(1, 2, 3).isInstanceOf[List[String]]
returning true andx.isInstanceOf[A]
whereA
is a type parameter or abstract member returning true, these forms issue a warning.
- def iterate[T](start: T, len: Int)(f: (T) => T)(implicit arg0: ClassTag[T]): Array[T]
Returns an array containing repeated applications of a function to a start value.
Returns an array containing repeated applications of a function to a start value.
- start
the start value of the array
- len
the number of elements returned by the array
- f
the function that is repeatedly applied
- returns
the array returning
len
values in the sequencestart, f(start), f(f(start)), ...
- final def ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that)
.Equivalent to
!(this eq that)
.- returns
true
if the argument is not a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
- def newBuilder[T](implicit t: ClassTag[T]): ArrayBuilder[T]
Returns a new scala.collection.mutable.ArrayBuilder.
- final def notify(): Unit
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
- final def notifyAll(): Unit
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
- def ofDim[T](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(implicit arg0: ClassTag[T]): Array[Array[Array[Array[Array[T]]]]]
Creates a 5-dimensional array
- def ofDim[T](n1: Int, n2: Int, n3: Int, n4: Int)(implicit arg0: ClassTag[T]): Array[Array[Array[Array[T]]]]
Creates a 4-dimensional array
- def ofDim[T](n1: Int, n2: Int, n3: Int)(implicit arg0: ClassTag[T]): Array[Array[Array[T]]]
Creates a 3-dimensional array
- def ofDim[T](n1: Int, n2: Int)(implicit arg0: ClassTag[T]): Array[Array[T]]
Creates a 2-dimensional array
- def ofDim[T](n1: Int)(implicit arg0: ClassTag[T]): Array[T]
Creates array with given dimensions
- def range(start: Int, end: Int, step: Int): Array[Int]
Returns an array containing equally spaced values in some integer interval.
Returns an array containing equally spaced values in some integer interval.
- start
the start value of the array
- end
the end value of the array, exclusive (in other words, this is the first value not returned)
- step
the increment value of the array (may not be zero)
- returns
the array with values in
start, start + step, ...
up to, but excludingend
- def range(start: Int, end: Int): Array[Int]
Returns an array containing a sequence of increasing integers in a range.
Returns an array containing a sequence of increasing integers in a range.
- start
the start value of the array
- end
the end value of the array, exclusive (in other words, this is the first value not returned)
- returns
the array with values in range
start, start + 1, ..., end - 1
up to, but excluding,end
.
- final def synchronized[T0](arg0: => T0): T0
Executes the code in
body
with an exclusive lock onthis
.Executes the code in
body
with an exclusive lock onthis
.- returns
the result of
body
- Definition Classes
- AnyRef
- def tabulate[T](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(f: (Int, Int, Int, Int, Int) => T)(implicit arg0: ClassTag[T]): Array[Array[Array[Array[Array[T]]]]]
Returns a five-dimensional array containing values of a given function over ranges of integer values starting from
0
.Returns a five-dimensional array containing values of a given function over ranges of integer values starting from
0
.- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3rd dimension
- n4
the number of elements in the 4th dimension
- n5
the number of elements in the 5th dimension
- f
The function computing element values
- def tabulate[T](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) => T)(implicit arg0: ClassTag[T]): Array[Array[Array[Array[T]]]]
Returns a four-dimensional array containing values of a given function over ranges of integer values starting from
0
.Returns a four-dimensional array containing values of a given function over ranges of integer values starting from
0
.- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3rd dimension
- n4
the number of elements in the 4th dimension
- f
The function computing element values
- def tabulate[T](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) => T)(implicit arg0: ClassTag[T]): Array[Array[Array[T]]]
Returns a three-dimensional array containing values of a given function over ranges of integer values starting from
0
.Returns a three-dimensional array containing values of a given function over ranges of integer values starting from
0
.- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3rd dimension
- f
The function computing element values
- def tabulate[T](n1: Int, n2: Int)(f: (Int, Int) => T)(implicit arg0: ClassTag[T]): Array[Array[T]]
Returns a two-dimensional array containing values of a given function over ranges of integer values starting from
0
.Returns a two-dimensional array containing values of a given function over ranges of integer values starting from
0
.- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- f
The function computing element values
- def tabulate[T](n: Int)(f: (Int) => T)(implicit arg0: ClassTag[T]): Array[T]
Returns an array containing values of a given function over a range of integer values starting from 0.
Returns an array containing values of a given function over a range of integer values starting from 0.
- n
The number of elements in the array
- f
The function computing element values
- returns
An
Array
consisting of elementsf(0),f(1), ..., f(n - 1)
- implicit def toFactory[A](dummy: Array.type)(implicit arg0: ClassTag[A]): Factory[A, Array[A]]
Provides an implicit conversion from the Array object to a collection Factory
- def toString(): String
Creates a String representation of this object.
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.
- returns
a String representation of the object.
- Definition Classes
- AnyRef → Any
- def unapplySeq[T](x: Array[T]): UnapplySeqWrapper[T]
Called in a pattern match like
{ case Array(x,y,z) => println('3 elements')}
.Called in a pattern match like
{ case Array(x,y,z) => println('3 elements')}
.- x
the selector value
- returns
sequence wrapped in a scala.Some, if
x
is an Array, otherwiseNone
- final def wait(): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait--.
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- Note
not specified by SLS as a member of AnyRef
- final def wait(arg0: Long, arg1: Int): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-int-
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- Note
not specified by SLS as a member of AnyRef
- final def wait(arg0: Long): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-.
This is the documentation for the Scala standard library.
Package structure
The scala package contains core types like
Int
,Float
,Array
orOption
which are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collection
and its sub-packages contain Scala's collections frameworkscala.collection.immutable
- Immutable, sequential data-structures such asVector
,List
,Range
,HashMap
orHashSet
scala.collection.mutable
- Mutable, sequential data-structures such asArrayBuffer
,StringBuilder
,HashMap
orHashSet
scala.collection.concurrent
- Mutable, concurrent data-structures such asTrieMap
scala.concurrent
- Primitives for concurrent programming such asFutures
andPromises
scala.io
- Input and output operationsscala.math
- Basic math functions and additional numeric types likeBigInt
andBigDecimal
scala.sys
- Interaction with other processes and the operating systemscala.util.matching
- Regular expressionsOther packages exist. See the complete list on the right.
Additional parts of the standard library are shipped as separate libraries. These include:
scala.reflect
- Scala's reflection API (scala-reflect.jar)scala.xml
- XML parsing, manipulation, and serialization (scala-xml.jar)scala.collection.parallel
- Parallel collections (scala-parallel-collections.jar)scala.util.parsing
- Parser combinators (scala-parser-combinators.jar)scala.swing
- A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)Automatic imports
Identifiers in the scala package and the
scala.Predef
object are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
List
is an alias forscala.collection.immutable.List
.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
String
is an alias forjava.lang.String
.