Using java streams to find if a number is prime or not

Question

I am reading Cracking the Coding Interview and it has an example of finding prime number which I ran on JShell

boolean isPrime(int n) {
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      return false;
    }
  }
  return true;
}

then I am trying to convert this to streams in java, but finding this difficult as mentioned

boolean isPrimeStream(int n) {
  return IntStream.range(0, n) // how to do similar to for loop above
    .anyMatch(i -> n % i == 0);  // i think this is the reason for failure
}

Answer 1

I am reading Cracking the Coding Interview and it has an example of finding prime number which I ran on JShell

boolean isPrime(int n) {
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      return false;
    }
  }
  return true;
}

then I am trying to convert this to streams in java, but finding this difficult as mentioned

boolean isPrimeStream(int n) {
  return IntStream.range(0, n) // how to do similar to for loop above
    .anyMatch(i -> n % i == 0);  // i think this is the reason for failure
}

Answer 2

I am reading Cracking the Coding Interview and it has an example of finding prime number which I ran on JShell

boolean isPrime(int n) {
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      return false;
    }
  }
  return true;
}

then I am trying to convert this to streams in java, but finding this difficult as mentioned

boolean isPrimeStream(int n) {
  return IntStream.range(0, n) // how to do similar to for loop above
    .anyMatch(i -> n % i == 0);  // i think this is the reason for failure
}

Answer 3

I am reading Cracking the Coding Interview and it has an example of finding prime number which I ran on JShell

boolean isPrime(int n) {
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      return false;
    }
  }
  return true;
}

then I am trying to convert this to streams in java, but finding this difficult as mentioned

boolean isPrimeStream(int n) {
  return IntStream.range(0, n) // how to do similar to for loop above
    .anyMatch(i -> n % i == 0);  // i think this is the reason for failure
}

Answer 4

package Java8Practice;

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class PrintPrimeNumbers {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    List<Integer> list = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
    List<Integer> primes = list.stream().filter(n -> isPrime(n)).collect(Collectors.toList());
    System.out.println(primes);
}

static boolean isPrime(int n) {
    return IntStream.range(2, n).noneMatch(i -> n % i == 0);
 }
}

/*Output 
[1, 2, 3, 5, 7]
*/