reduce
public class Example {
public static void main(String[] args) {
int total = numbers.stream().reduce(0, Integer::sum);
Optional<Integer> product = numbers.stream().reduce((a, b) -> a * b);
int sum = numbers.stream().mapToInt(Integer::intValue).sum();
}
}
The identity must be a true identity for the operation — wrong identities break parallel streams.
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Still to come · 1 section
- Primitive streams
Test yourself
Answer these before moving on — recall is what makes it stick.