lift and unlift do not evaluate source functions twice on each invocation.combining partial functions into orElse/ andThen chains does not lead to.This makes applyOrElse the basis for the efficient implementation for many operations and scenarios, such as: Note that expression pf.applyOrElse(x, default) is equivalent to if(pf isDefinedAt x) pf(x) else default(x)Įxcept that applyOrElse method can be implemented more efficiently.įor all partial function literals the compiler generates an applyOrElse implementation whichĪvoids double evaluation of pattern matchers and guards. Definition Classes rootĪpplies this partial function to the given argument when it is contained in the function domain.Īpplies fallback function where this partial function is not defined. For example, on the JVM, String is an alias for. Other aliases refer to classes provided by the underlying platform. Some of these identifiers are type aliases provided as shortcuts to commonly used classes. Identifiers in the scala package and the scala.Predef object are always in scope by default. scala.swing - A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar).- Parser combinators (scala-parser-combinators.jar).- Parallel collections (scala-parallel-collections.jar).scala.xml - XML parsing, manipulation, and serialization (scala-xml.jar).scala.reflect - Scala's reflection API (scala-reflect.jar).See the complete list on the right.Īdditional parts of the standard library are shipped as separate libraries.

scala.sys - Interaction with other processes and the operating system.scala.math - Basic math functions and additional numeric types like.ncurrent - Primitives for concurrent programming such as.- Mutable, concurrent data-structures such as.

- Mutable, sequential data-structures such as.

- Immutable, sequential data-structures such as.

llection and its sub-packages contain Scala's collections framework.

Or Option which are accessible in all Scala compilation units without explicit qualification or The scala package contains core types like Int, Float, Array This is the documentation for the Scala standard library.

Scala filter method map