case class StringContext(parts: String*) extends Product with Serializable
This class provides the basic mechanism to do String Interpolation. String Interpolation allows users to embed variable references directly in *processed* string literals. Here's an example:
val name = "James" println(s"Hello, $name") // Hello, James
Any processed string literal is rewritten as an instantiation and method call against this class. For example:
s"Hello, $name"is rewritten to be:
StringContext("Hello, ", "").s(name)
By default, this class provides the raw, s and f methods as
available interpolators.
To provide your own string interpolator, create an implicit class
which adds a method to StringContext. Here's an example:
implicit class JsonHelper(private val sc: StringContext) extends AnyVal { def json(args: Any*): JSONObject = ... } val x: JSONObject = json"{ a: $a }"
Here the JsonHelper extension class implicitly adds the json method to
StringContext which can be used for json string literals.
- parts
The parts that make up the interpolated string, without the expressions that get inserted by interpolation.
- Source
- StringContext.scala
- Since
2.10.0
- Alphabetic
- By Inheritance
- StringContext
- Serializable
- Serializable
- Product
- Equals
- AnyRef
- Any
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
- Hide All
- Show All
- Public
- All
Instance Constructors
Value Members
-
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
-
def
+(other: String): String
- Implicit
- This member is added by an implicit conversion from StringContext to any2stringadd[StringContext] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
-
def
->[B](y: B): (StringContext, B)
- Implicit
- This member is added by an implicit conversion from StringContext to ArrowAssoc[StringContext] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
-
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
-
final
def
asInstanceOf[T0]: T0
Cast the receiver object to be of type
T0.Cast the receiver object to be of type
T0.Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression
1.asInstanceOf[String]will throw aClassCastExceptionat runtime, while the expressionList(1).asInstanceOf[List[String]]will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.- returns
the receiver object.
- Definition Classes
- Any
- Exceptions thrown
ClassCastExceptionif the receiver object is not an instance of the erasure of typeT0.
-
def
checkLengths(args: Seq[Any]): Unit
Checks that the length of the given argument
argsis one less than the number ofpartssupplied to the enclosingStringContext.Checks that the length of the given argument
argsis one less than the number ofpartssupplied to the enclosingStringContext.- Exceptions thrown
IllegalArgumentExceptionif this is not the case.
-
def
clone(): AnyRef
Create a copy of the receiver object.
-
def
ensuring(cond: (StringContext) ⇒ Boolean, msg: ⇒ Any): StringContext
- Implicit
- This member is added by an implicit conversion from StringContext to Ensuring[StringContext] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
def
ensuring(cond: (StringContext) ⇒ Boolean): StringContext
- Implicit
- This member is added by an implicit conversion from StringContext to Ensuring[StringContext] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
def
ensuring(cond: Boolean, msg: ⇒ Any): StringContext
- Implicit
- This member is added by an implicit conversion from StringContext to Ensuring[StringContext] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
def
ensuring(cond: Boolean): StringContext
- Implicit
- This member is added by an implicit conversion from StringContext to Ensuring[StringContext] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
-
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
-
macro
def
f[A >: Any](args: A*): String
The formatted string interpolator.
The formatted string interpolator.
It inserts its arguments between corresponding parts of the string context. It also treats standard escape sequences as defined in the Scala specification. Finally, if an interpolated expression is followed by a
partsstring that starts with a formatting specifier, the expression is formatted according to that specifier. All specifiers allowed in Java format strings are handled, and in the same way they are treated in Java.For example:
val height = 1.9d val name = "James" println(f"$name%s is $height%2.2f meters tall") // James is 1.90 meters tall
- Exceptions thrown
IllegalArgumentExceptionif the number ofpartsin the enclosingStringContextdoes not exceed the number of argumentsargby exactly 1.if a
partsstring contains a backslash (\) character that does not start a valid escape sequence. Note: Thefmethod works by assembling a format string from all thepartsstrings and usingjava.lang.String.formatto format all arguments with that format string. The format string is obtained by concatenating allpartsstrings, and performing two transformations:- Let a _formatting position_ be a start of any
partsstring except the first one. If a formatting position does not refer to a%character (which is assumed to start a format specifier), then the string format specifier%sis inserted. 2. Any%characters not in formatting positions must begin one of the conversions%%(the literal percent) or%n(the platform-specific line separator).
- Let a _formatting position_ be a start of any
-
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. -
def
formatted(fmtstr: String): String
Returns string formatted according to given
formatstring.Returns string formatted according to given
formatstring. Format strings are as forString.format(@see java.lang.String.format).- Implicit
- This member is added by an implicit conversion from StringContext to StringFormat[StringContext] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @inline()
-
final
def
getClass(): Class[_]
Returns the runtime class representation of the object.
-
final
def
isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object is
T0.Test whether the dynamic type of the receiver object is
T0.Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression
1.isInstanceOf[String]will returnfalse, while the expressionList(1).isInstanceOf[List[String]]will returntrue. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.- returns
trueif the receiver object is an instance of erasure of typeT0;falseotherwise.
- Definition Classes
- Any
-
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
-
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 parts: String*
-
def
raw(args: Any*): String
The raw string interpolator.
The raw string interpolator.
It inserts its arguments between corresponding parts of the string context. As opposed to the simple string interpolator
s, this one does not treat standard escape sequences as defined in the Scala specification.For example, the raw processed string
raw"a\nb"is equal to the scala string"a\\nb".Note: Even when using the raw interpolator, Scala will preprocess unicode escapes. For example:
scala> raw"\u0023" res0: String = #
- Exceptions thrown
IllegalArgumentExceptionif the number ofpartsin the enclosingStringContextdoes not exceed the number of argumentsargby exactly 1.- Note
The Scala compiler may replace a call to this method with an equivalent, but more efficient, use of a StringBuilder.
-
def
s(args: Any*): String
The simple string interpolator.
The simple string interpolator.
It inserts its arguments between corresponding parts of the string context. It also treats standard escape sequences as defined in the Scala specification. Here's an example of usage:
val name = "James" println(s"Hello, $name") // Hello, James
In this example, the expression $name is replaced with the
toStringof the variablename. Thesinterpolator can take thetoStringof any arbitrary expression within a${}block, for example:println(s"1 + 1 = ${1 + 1}")will print the string
1 + 1 = 2.- Exceptions thrown
IllegalArgumentExceptionif the number ofpartsin the enclosingStringContextdoes not exceed the number of argumentsargby exactly 1.StringContext.InvalidEscapeExceptionif apartsstring contains a backslash (\) character that does not start a valid escape sequence.- Note
The Scala compiler may replace a call to this method with an equivalent, but more efficient, use of a StringBuilder.
- def standardInterpolator(process: (String) ⇒ String, args: Seq[Any]): String
-
final
def
synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
-
final
def
wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
- final def wait(arg0: Long): Unit
-
def
→[B](y: B): (StringContext, B)
- Implicit
- This member is added by an implicit conversion from StringContext to ArrowAssoc[StringContext] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
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.collection.parallel.immutable- Immutable, parallel data-structures such asParVector,ParRange,ParHashMaporParHashSetscala.collection.parallel.mutable- Mutable, parallel data-structures such asParArray,ParHashMap,ParTrieMaporParHashSetscala.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.swing- A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)scala.util.parsing- Parser combinators (scala-parser-combinators.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.