How to convert Stream<int[]> to Stream<Integer>

user_1664430 0
Viewed 1793

Is there a way convert Stream<int[]> to Stream<Integer>

int[] arr2 = new int[] { 54, 432, 53, 21, 43 };
// Below gives me Stream<int[]> 

Stream.of(arr2);  // I want to convert it to Stream<Integer>
java-stream java-8 java
5 Answers

You can use either Arrays.stream()

Arrays.stream(arr2).boxed();  // will return Stream<Integer>

Or IntStream.of

IntStream.of(arr2).boxed();   // will return Stream<Integer>

Stream<Integer> boxed()

Returns a Stream consisting of the elements of this stream, each boxed to an Integer.

This is an intermediate operation.

user_99591520

box the stream:

Arrays.stream(arr2).boxed();
user_58620710

You can use this:

Integer[] arr = Arrays.stream(arr2).boxed().toArray(Integer[]::new);
user_25491100

You can create Stream from io.vavr with

Stream.ofAll(arr2)

but you want to use stream of integers you should use IntStream. You can create IntStream from array like this:

Arrays.stream(arr2)
user_89712740

There is an issue in this case.

Let's look at an example. If you have an array of primitives and try to create a stream directly you will have a stream of one array object, like this:

// Arrays of primitives 
int[] nums = {1, 2, 3, 4, 5}; 
Stream.of(nums); // One element int[] | Stream<int[]>

To solve this you can use:

Arrays.stream(nums).count();  // Five Elements 
IntStream.of(nums).count(); // Five Elements
user_104514720
Related