object Random extends Random
The object Random offers a default implementation
of scala.util.Random and random-related convenience methods.
- Source
- Random.scala
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- Random
- Random
- Serializable
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- final def !=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
- returns
trueif !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
- final def ##: Int
Equivalent to
x.hashCodeexcept for boxed numeric types andnull.Equivalent to
x.hashCodeexcept 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. Fornullreturns a hashcode wherenull.hashCodethrows aNullPointerException.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
- final def ==(arg0: Any): Boolean
The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).- returns
trueif the receiver object is equivalent to the argument;falseotherwise.
- Definition Classes
- AnyRef → Any
- def alphanumeric: collection.immutable.LazyList[Char]
Returns a LazyList of pseudorandomly chosen alphanumeric characters, equally chosen from A-Z, a-z, and 0-9.
Returns a LazyList of pseudorandomly chosen alphanumeric characters, equally chosen from A-Z, a-z, and 0-9.
- Definition Classes
- Random
- Annotations
- @migration
- Migration
(Changed in version 2.13.0)
alphanumericreturns a LazyList instead of a Stream
- 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
asInstanceOfhas 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,
asInstanceOfis 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
asInstanceOfis useful:- when flow analysis fails to deduce
T0automatically - 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
asInstanceOfwhenT0is a primitive type. WhenT0is primitive,asInstanceOfmay insert a conversion instead of a type test. If your intent is to convert, use atoTmethod (x.toChar,x.toByte, etc.).- returns
the receiver object.
- Definition Classes
- Any
- Exceptions thrown
ClassCastExceptionif 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 between(minInclusive: Long, maxExclusive: Long): Long
Returns a pseudorandom, uniformly distributed long value between min (inclusive) and the specified value max (exclusive), drawn from this random number generator's sequence.
Returns a pseudorandom, uniformly distributed long value between min (inclusive) and the specified value max (exclusive), drawn from this random number generator's sequence.
- Definition Classes
- Random
- def between(minInclusive: Int, maxExclusive: Int): Int
Returns a pseudorandom, uniformly distributed int value between min (inclusive) and the specified value max (exclusive), drawn from this random number generator's sequence.
Returns a pseudorandom, uniformly distributed int value between min (inclusive) and the specified value max (exclusive), drawn from this random number generator's sequence.
- Definition Classes
- Random
- def between(minInclusive: Float, maxExclusive: Float): Float
Returns the next pseudorandom, uniformly distributed float value between min (inclusive) and max (exclusive) from this random number generator's sequence.
Returns the next pseudorandom, uniformly distributed float value between min (inclusive) and max (exclusive) from this random number generator's sequence.
- Definition Classes
- Random
- def between(minInclusive: Double, maxExclusive: Double): Double
Returns the next pseudorandom, uniformly distributed double value between min (inclusive) and max (exclusive) from this random number generator's sequence.
Returns the next pseudorandom, uniformly distributed double value between min (inclusive) and max (exclusive) from this random number generator's sequence.
- Definition Classes
- Random
- def clone(): AnyRef
Create a copy of the receiver object.
Create a copy of the receiver object.
The default implementation of the
clonemethod is platform dependent.- returns
a copy of the receiver object.
- 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
eqmethod implements an equivalence relation on non-null instances ofAnyRef, and has three additional properties:- It is consistent: for any non-null instances
xandyof typeAnyRef, multiple invocations ofx.eq(y)consistently returnstrueor consistently returnsfalse. - For any non-null instance
xof typeAnyRef,x.eq(null)andnull.eq(x)returnsfalse. null.eq(null)returnstrue.
When overriding the
equalsorhashCodemethods, 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
trueif the argument is a reference to the receiver object;falseotherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
- def equals(arg0: AnyRef): Boolean
The equality method for reference types.
- 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
finalizemethod is invoked, as well as the interaction betweenfinalizeand 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
- 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
T0is, the test is done in one of the below ways:T0is a non-parameterized class type, e.g.BigDecimal: this method returnstrueif the value of the receiver object is aBigDecimalor a subtype ofBigDecimal.T0is a parameterized class type, e.g.List[Int]: this method returnstrueif the value of the receiver object is someList[X]for anyX. For example,List(1, 2, 3).isInstanceOf[List[String]]will return true.T0is some singleton typex.typeor literalx: this method returnsthis.eq(x). For example,x.isInstanceOf[1]is equivalent tox.eq(1)T0is an intersectionX with YorX & Y: this method is equivalent tox.isInstanceOf[X] && x.isInstanceOf[Y]T0is a unionX | Y: this method is equivalent tox.isInstanceOf[X] || x.isInstanceOf[Y]T0is a type parameter or an abstract type member: this method is equivalent toisInstanceOf[U]whereUisT0's upper bound,AnyifT0is unbounded. For example,x.isInstanceOf[A]whereAis an unbounded type parameter will return true for any value ofx.
This is exactly equivalent to the type pattern
_: T0- returns
trueif the receiver object is an instance of erasure of typeT0;falseotherwise.
- Definition Classes
- Any
- Note
due to the unexpectedness of
List(1, 2, 3).isInstanceOf[List[String]]returning true andx.isInstanceOf[A]whereAis a type parameter or abstract member returning true, these forms issue a warning.
- implicit def javaRandomToRandom(r: java.util.Random): Random
- final def ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that).Equivalent to
!(this eq that).- returns
trueif the argument is not a reference to the receiver object;falseotherwise.
- Definition Classes
- AnyRef
- def nextBoolean(): Boolean
Returns the next pseudorandom, uniformly distributed boolean value from this random number generator's sequence.
Returns the next pseudorandom, uniformly distributed boolean value from this random number generator's sequence.
- Definition Classes
- Random
- def nextBytes(n: Int): Array[Byte]
Generates
nrandom bytes and returns them in a new array.Generates
nrandom bytes and returns them in a new array.- Definition Classes
- Random
- def nextBytes(bytes: Array[Byte]): Unit
Generates random bytes and places them into a user-supplied byte array.
Generates random bytes and places them into a user-supplied byte array.
- Definition Classes
- Random
- def nextDouble(): Double
Returns the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence.
Returns the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence.
- Definition Classes
- Random
- def nextFloat(): Float
Returns the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence.
Returns the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence.
- Definition Classes
- Random
- def nextGaussian(): Double
Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.
Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.
- Definition Classes
- Random
- def nextInt(n: Int): Int
Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
- Definition Classes
- Random
- def nextInt(): Int
Returns the next pseudorandom, uniformly distributed int value from this random number generator's sequence.
Returns the next pseudorandom, uniformly distributed int value from this random number generator's sequence.
- Definition Classes
- Random
- def nextLong(n: Long): Long
Returns a pseudorandom, uniformly distributed long value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
Returns a pseudorandom, uniformly distributed long value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
- Definition Classes
- Random
- def nextLong(): Long
Returns the next pseudorandom, uniformly distributed long value from this random number generator's sequence.
Returns the next pseudorandom, uniformly distributed long value from this random number generator's sequence.
- Definition Classes
- Random
- def nextPrintableChar(): Char
Returns the next pseudorandom, uniformly distributed value from the ASCII range 33-126.
Returns the next pseudorandom, uniformly distributed value from the ASCII range 33-126.
- Definition Classes
- Random
- def nextString(length: Int): String
Returns a pseudorandomly generated String.
Returns a pseudorandomly generated String. This routine does not take any measures to preserve the randomness of the distribution in the face of factors like unicode's variable-length encoding, so please don't use this for anything important. It's primarily intended for generating test data.
- length
the desired length of the String
- returns
the String
- Definition Classes
- Random
- 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
- val self: java.util.Random
- Definition Classes
- Random
- def setSeed(seed: Long): Unit
- Definition Classes
- Random
- def shuffle[T, C](xs: IterableOnce[T])(implicit bf: BuildFrom[xs.type, T, C]): C
Returns a new collection of the same type in a randomly chosen order.
Returns a new collection of the same type in a randomly chosen order.
- returns
the shuffled collection
- Definition Classes
- Random
- final def synchronized[T0](arg0: => T0): T0
Executes the code in
bodywith an exclusive lock onthis.Executes the code in
bodywith an exclusive lock onthis.- returns
the result of
body
- Definition Classes
- AnyRef
- 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
- 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,ArrayorOptionwhich are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collectionand its sub-packages contain Scala's collections frameworkscala.collection.immutable- Immutable, sequential data-structures such asVector,List,Range,HashMaporHashSetscala.collection.mutable- Mutable, sequential data-structures such asArrayBuffer,StringBuilder,HashMaporHashSetscala.collection.concurrent- Mutable, concurrent data-structures such asTrieMapscala.concurrent- Primitives for concurrent programming such asFuturesandPromisesscala.io- Input and output operationsscala.math- Basic math functions and additional numeric types likeBigIntandBigDecimalscala.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.Predefobject are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
Listis an alias forscala.collection.immutable.List.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
Stringis an alias forjava.lang.String.