Skip to content

E Primitive Streams.md

Latest commit

 

History

History
42 lines (34 loc) · 1.31 KB

E Primitive Streams.md

File metadata and controls

42 lines (34 loc) · 1.31 KB

Primitive Streams

Boxing int into Integer for every element is expensive. Java provides three specialised primitive streams that avoid this overhead:

Stream Element type Useful extras
IntStream int sum(), average(), range()
LongStream long sum(), average(), range()
DoubleStream double sum(), average() 
// Sum 1 to 10 without boxing
var total = IntStream.rangeClosed(1, 10).sum();
System.out.println(total); // 55

// Average salary using mapToDouble
var avg = List.of(50_000, 75_000, 90_000).stream()
        .mapToDouble(Integer::doubleValue)
        .average()
        .orElse(0);

System.out.println(avg); // 71666.66...

Convert back to an object stream with .boxed():

List<Integer> list = IntStream.range(1, 6).boxed().toList();
System.out.println(list); // [1, 2, 3, 4, 5]
Previous: C How To Create A Stream?.md Next: E Structure Of A Stream Pipeline.md