Function Currying is a concept of breaking a function with many arguments into many functions with single argument in such a way, that the output is same. In other words, its a technique of simplifying a multi-valued argument function into single-valued argument multi-functions.
Consider the example to clear the concept:
Currying breaks down higher order functions into a series of smaller cascaded functions which take in one argument and return a function except for the last cascaded function which returns the desired value.
For example:
Let there be a function which maps as
Currying the above function will produce
Thus maps from to a function which in turn maps from to
The above mathematical expression can also be represented as:
Hence,
Below are some examples in Java to demonstrate Function Currying:
Example 1: Adding 2 numbers using Function Currying
// Java Program to demonstrate Function Currying  import java.util.function.Function;  public class GFG {    public static void main(String args[])    {          // Using Java 8 Functions        // to create lambda expressions for functions        // and with this, applying Function Currying          // Curried Function for Adding u & v        Function<Integer,                 Function<Integer, Integer> >            curryAdder = u -> v -> u + v;          // Calling the curried functions          // Calling Curried Function for Adding u & v        System.out.println("Add 2, 3 :"                           + curryAdder                                 .apply(2)                                 .apply(3));          }} |
Add 2, 3 :5
Example 2: Multiplying 2 numbers using Function Currying
// Java Program to demonstrate Function Currying  import java.util.function.Function;  public class GFG {    public static void main(String args[])    {          // Using Java 8 Functions        // to create lambda expressions for functions        // and with this, applying Function Currying          // Curried Function for Multiplying u & v        Function<Integer,                 Function<Integer, Integer> >            curryMulti = u -> v -> u * v;          // Calling the curried functions                 // Calling Curried Function for Multiplying u & v        System.out.println("Multiply 2, 3 :"                           + curryMulti                                 .apply(2)                                 .apply(3));    }} |
Multiply 2, 3 :6
Example 3: Adding 3 numbers using Function Currying
// Java Program to demonstrate Function Currying  import java.util.function.Function;  public class GFG {    public static void main(String args[])    {          // Using Java 8 Functions        // to create lambda expressions for functions        // and with this, applying Function Currying          // Curried Function for Adding u, v & w        Function<Integer,                 Function<Integer,                          Function<Integer, Integer> > >            triadder = u -> w -> v -> u + w + v;          // Calling the curried functions          // Calling Curried Function for Adding u, v & w        System.out.println("Add 2, 3, 4 :"                           + triadder                                 .apply(2)                                 .apply(3)                                 .apply(4));    }} |
Add 2, 3, 4 :9
