Stream mapToInt() in Java with examples
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.
Syntax :
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.
import java.util.*;
class GFG {
public static void main(String[] args)
{
List<String> list = Arrays.asList( "3" , "6" , "8" ,
"14" , "15" );
list.stream().mapToInt(num -> Integer.parseInt(num))
.filter(num -> num % 3 == 0 )
.forEach(System.out::println);
}
}
|
Output :
3
6
15
Example 2 : mapToInt() to return IntStream after performing operation of mapping string with its length.
import java.util.*;
class GFG {
public static void main(String[] args)
{
List<String> list = Arrays.asList( "Geeks" , "for" , "gfg" ,
"GeeksforGeeks" , "GeeksQuiz" );
list.stream().mapToInt(str -> str.length()).forEach(System.out::println);
}
}
|
Output :
5
3
3
13
9
Last Updated :
06 Dec, 2018
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