Ints toArray() function | Guava | Java

Guava’s Ints.toArray() returns an array containing each value of collection, converted to a int value in the manner of Number.intValue()

Syntax:

public static int[] 
    toArray(Collection<? extends Number> collection)

Parameters: This method takes the collection as parameter which is a collection of Number instances.

Return Value: This method returns an array containing the same values as collection, in the same order, converted to primitives.

Exceptions: This method throws NullPointerException if collection or any of its elements is null.



Below examples illustrate the Ints.toArray() method:

Example 1:

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java code to show implementation of
// Guava's Ints.toArray() method
  
import com.google.common.primitives.Ints;
import java.util.Arrays;
import java.util.List;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
  
        // Creating a List of Integers
        List<Integer>
            myList = Arrays.asList(1, 2, 3, 4, 5);
  
        // Using Ints.toArray() method to convert
        // a List or Set of Integer to an array
        // of Int
        int[] arr = Ints.toArray(myList);
  
        // Displaying an array containing each
        // value of collection,
        // converted to a int value
        System.out.println("Array from given List: "
                           + Arrays.toString(arr));
    }
}

chevron_right


Output:

Array from given List: [1, 2, 3, 4, 5]

Example 2: To demonstrate NullPointerException

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java code to show implementation of
// Guava's Ints.toArray() method
  
import com.google.common.primitives.Ints;
import java.util.Arrays;
import java.util.List;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
  
        try {
  
            // Creating a List of Integers
            List<Integer>
                myList = Arrays.asList(2, 4, null);
  
            // Using Ints.toArray() method to convert
            // a List or Set of Integer to an array
            // of Int. This should raise "NullPointerException"
            // as the collection contains "null" as an element
            int[] arr = Ints.toArray(myList);
  
            // Displaying an array containing each
            // value of collection, converted to a int value
            System.out.println(Arrays.toString(arr));
        }
        catch (Exception e) {
            System.out.println("Exception: " + e);
        }
    }
}

chevron_right


Output:

Exception: java.lang.NullPointerException

Reference: https://google.github.io/guava/releases/22.0/api/docs/com/google/common/primitives/Ints.html#toArray-java.util.Collection-



My Personal Notes arrow_drop_up

In love with a semicolon because sometimes i miss it so badly)

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.




Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.