Stream mapToInt(ToIntFunction mapper) returns an IntStream consisting of the results of applying the given function to the elements of this stream.
Stream mapToInt(ToIntFunction mapper) is an intermediate operation. These operations are always lazy. Intermediate operations are invoked on a Stream instance and after they finish their processing, they give a Stream instance as output.
IntStream mapToInt(ToIntFunction<? super T> mapper) Where, IntStream is a sequence of primitive int-valued elements and T is the type of stream elements. mapper is a stateless function which is applied to each element and the function returns the new stream.
Example 1 : mapToInt() with operation of printing the stream element if divisible by 3.
3 6 15
Example 2 : mapToInt() to return IntStream after performing operation of mapping string with its length.
5 3 3 13 9
Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more, please refer Complete Interview Preparation Course.