Currying Functions in Scala

Currying Function

Currying in Scala is simply a technique or a process of transforming a function. This function takes multiple arguments into a function that takes single argument. It is applied widely in multiple functional languages.

Syntax

def function name(argument1, argument2) = operation

Example:

object Curry

{

    // Define currying function

    def multiply(x: Int, y: Int) = x * y;

 

    def main(args: Array[String])

    {

        println(multiply(20, 19));

    }

}

//Output

380

Another way to declare currying function

we have to transform this add function into a Curried function, that is transforming the function that takes two(multiple) arguments into a function that takes one(single) argument.

Syntax

def function name(argument1) = (argument2) => operation

Example:

object Curry

{

    // transforming the function that takes two(multiple) arguments into a function that takes one(single) argument.

    def multiply(a: Int) = (b: Int) => a * b;

    // Main method

    def main(args: Array[String])

    {

        println(multiply(20)(19));

    }

}

//Output

380

Currying Function Using Partial Application

We have another way to use this Curried function and that is Partially Applied function. So, let’s take a simple example and understand. we have defined a variable sum in the main function

Example:

object Curry

{

    def multiply(a: Int) = (b: Int) => a * b;

    // Main function

    def main(args: Array[String])

    {

        // Partially Applied function.

        val mult = multiply(29);

                        //val mult=multiply(29)_;

        println(mult(5));

    }

}

//Output

145

Also, another way(syntax) to write the currying function.

Syntax

def function name(argument1) (argument2) = operation

Example:

object Curry

{

    // Curring function declaration

    def multiply(a: Int) (b: Int) = a * b;

 

    def main(args: Array[String])

    {

        println(multiply(29)(5));

    }

}

//Output

145