CODEWITHSUNDEEP
javalambdajava-stream
IUnknown
IUnknown

Reputation: 9809

Lambda not resolving type

I see a strange issue where eclipse is not dentifying my lambda arguments

public static void main(String[] args) {
    int[] array = {23,43,56,97,32};
    int sum1 = Arrays.asList(array).stream().reduce(0, (total, e) -> total + e).intValue(); 
}

I get total and e cannot be resolved to a variable.
I see examples where 'total' and 'e' are used as arguments without declaring.
However,in my case - it refuses to compile without declaring.
What is the issue here?

Upvotes: 1

Views: 109

Answers (3)

Eugene
Eugene

Reputation: 120858

Arrays.asList(int[]) - will create a List<int[]>

You should have it like this:

int sum1 = Arrays.asList(23, 43, 56, 97, 32)
                 .stream().reduce(0, (total, e) -> total + e).intValue();

Upvotes: 3

Flown
Flown

Reputation: 11740

Simply use:

int[] array = {23,43,56,97,32};
int sum1 = Arrays.stream(array).reduce(0, (total, e) -> total + e);

I've changed Arrays.asList(...).stream(), which produces Stream<int[]>, to Arrays.stream(...) (or IntStream.of(...)).

In addition to this you can simplify the reduction to:

int sum1 = Arrays.stream(array).sum();

Upvotes: 0

Eran
Eran

Reputation: 393841

Arrays.asList(array) for a primitive array returns a List whose single element is that array.

Change

Arrays.asList(array).stream()

to

Arrays.stream(array)

Note this will give to an IntStream, not a Stream<Integer>, so no need for intValue() at the end:

int sum1 = Arrays.stream(array).reduce(0, (total, e) -> total + e);

For a Stream<Integer> you can write:

Arrays.stream(array).boxed()

and the full line will be:

int sum1 = Arrays.stream(array).boxed().reduce(0, (total, e) -> total + e).intValue ();

Of course you can simply obtain the sum with:

int sum1 = Arrays.stream(array).sum ();

Upvotes: 5

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