Java 8 | Collectors averagingInt() with Examples ❤️

Collectors averagingInt(ToIntFunction<? super T> mapper)

arithmetic mean

Syntax:

public static 
   <T> Collector<T, ?, Double> 
     averagingInt(ToIntFunction<? super T> mapper)

Interface Collector<T, A, R>: A mutable reduction operation that accumulates input elements into a mutable result container, optionally transforming the accumulated result into a final representation after all input elements have been processed. Reduction operations can be performed either sequentially or in parallel.
- T: The type of input elements to the reduction operation.
- A: The mutable accumulation type of the reduction operation.
- R: The result type of the reduction operation.
Double: The Double class wraps a value of the primitive type double in an object. An object of type Double contains a single field whose type is double.
ToIntFunction: Represents a function that produces an int-valued result.

Parameters:

mapper

ToIntFunction

Program 1:

// Java code to show the implementation of 
// Collectors averagingInt(ToIntFunction mapper) function 
  
import java.util.stream.Collectors; 
import java.util.stream.Stream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
  
        // creating a string stream with numbers 
        Stream<String> s = Stream.of("3", "4", "5"); 
  
        // using Collectors averagingInt(ToIntFunction mapper) 
        // method to find arithmetic mean of inputs given 
        double ans = s 
                         .collect(Collectors 
                                      .averagingInt( 
                                          num -> Integer.parseInt(num))); 
  
        // displaying the result 
        System.out.println(ans); 
    } 
} 

Output:

4.0

Program 2:

// Java code to show the implementation of 
// Collectors averagingInt(ToIntFunction mapper) function 
  
import java.util.stream.Collectors; 
import java.util.stream.Stream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
        // creating a empty string stream 
        Stream<String> s = Stream.of(); 
  
        // using Collectors averagingInt(ToIntFunction mapper) 
        // method to find arithmetic mean of inputs given 
        double ans = s 
                         .collect(Collectors 
                                      .averagingInt( 
                                          num -> Integer.parseInt(num))); 
  
        // displaying the result 
        System.out.println(ans); 
    } 
} 

Output:

0.0

Program 3:

// Java code to show the implementation of 
// Collectors averagingInt(ToIntFunction mapper) function 
  
import java.util.stream.Collectors; 
import java.util.stream.Stream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
        // creating a string stream 
        Stream<String> s = Stream.of("7", "8", "9", "10"); 
  
        // using Collectors averagingInt(ToIntFunction mapper) 
        // method to find arithmetic mean of inputs given 
        double ans = s 
                         .collect(Collectors 
                                      .averagingInt( 
                                          num -> Integer.parseInt(num))); 
  
        // displaying the result 
        System.out.println(ans); 
    } 
} 

Output:

8.5

Java 8 | Collectors averagingInt() with Examples

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