Scala Lang has many different symbols used in its syntax. Below is the list of symbols and their use in Scala language.
- “->” arrow symbol in Scala syntax returns a two-element tuple containing the key and value. You can use this symbol as shown in the below example-
Map(1->"Allan", 2->"Bob") (1).->("A)
- “_” underscore symbol in scala syntax is intended as a place holder, used in imports, functions literals.
import com.kodehelp.scala._ case_=> value.toString
- “:” colon symbol in scala syntax act as a separator between identifiers and type annotations.
def add(i:int):Int= ...
- “=” equal symbol in scala act as assignment operator
val ten = 10
- “=>” symbol is used in function literals to separate the argument list from the function body
numbers.filter(x => x)
- “<-” symbol is used for comprehensions in generator expressions
for(obj <- objects)
- “<:” symbol is called as Upper bound (a subtype of) and is used in parameterized and abstract type declaration to constrain the allowed types.
def apply[T <: U](x:T)
- “<%” symbol is called as view bound (apply implicit conversion) and is used in parameterized and abstract type declaration to convert the type using the view.
- “>:” symbol is called lower bound (super type of) and is used in parameterized and abstract type declarations to constrain the allowed types.
def append[U >:T(x:U)]
- “#” symbol is used to refer to a type declaration nested in another type
val ic: MyClass#myType
- “@” sybmol marks an annotation
@deprecated def sum() = ...
I hope these symbols used in Scala syntax helps you get started with Scala Programming language.