package java8sample;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.stream.Collectors;
public class streammain {
public static void main(String[] args) {
// Given a list of integers, find out all the even numbers that exist in the list using Stream functions?
List<Integer> intList = Arrays.asList(1,4,6,7,8,9,1,7);
List<Integer> intList1 = Arrays.asList(1,4,6);
List<Integer> evenList = intList.stream().filter(num -> num%2 == 0).collect(Collectors.toList());
// System.out.println("find out all the even numbers - "+evenList);
//multile by 2
// intList.stream().map(a -> a*2).forEach(System.out::print);
//sort
// StringBuilder s =
//filter and sort
List<Integer> l1 = intList.stream().filter(s -> s<=9).sorted().collect(Collectors.toList());
// System.out.println("filter and sort =- "+l1);
//Integer to string list, concat last but 1
List<String> s1 = l1.parallelStream().map(Object::toString).collect(Collectors.toList());
// System.out.println("Integer to string list, concat:");
// s1.stream().map(a -> a == s1.get(s1.size()-1)?a:a.concat(",")).forEach(System.out::print);
//Program to filter even numbers from an array using Java streams
Integer[] intArr = {1,3,12,5,6};
// Arrays.asList(intArr).stream().filter(num -> num%2 == 0).forEach(System.out::println);
Arrays.asList(intArr).stream().filter(num -> num%2 == 0).collect(Collectors.toList());
// List of numbers, find starting with 1
List<Integer> start1List = intList.stream().map(num -> (String.valueOf(num).startsWith("1") == true ? num : null)).filter(n -> n != null).collect(Collectors.toList());
// System.out.println(start1List);
// find three maximum and three minimum numbers from the list you can use the same list
// intList.stream().sorted().limit(3).forEach(System.out::println);
// intList.stream().sorted(Comparator.reverseOrder()).limit(3).forEach(System.out::println);
//add all values
// System.out.println(intList.stream().reduce(0, (x, y)->x+y));
//find duplicates values
// intList.stream().filter(s -> Collections.frequency(intList, s) > 1).forEach(System.out::print);
// use has set
HashSet<Integer> set1 = new HashSet<Integer>();
// intList.stream().filter(s -> !set1.add(s)).forEach(System.out::print);
//find second highest nos
// System.out.println(intList.stream().sorted(Comparator.reverseOrder()).limit(2).skip(1).findFirst().get());
// streammain sm = new streammain();
// sm.printPrime();
// Find the intersection of two lists using Java streams:
intList.stream().filter(intList1::contains).forEach(System.out::println);
}
// public boolean isPrime(Integer in) {
// if(in <= 1)
// return false;
// for(int i=2;i<in;i++) {
// if(in%i == 0)
// return false;
// }
// return true;
// }//end isPrime
public boolean isPrime(int number) {
if (number <= 1) {
return false;
}
for (int i = 2; i <= Math.sqrt(number); i++) {
if (number % i == 0) {
return false;
}
}
return true;
}
private void printPrime() {
List<Integer> numbers = Arrays.asList(2, 4, 6, 8, 10, 11, 12, 13, 14, 15);
boolean containsPrime = numbers.stream()
.anyMatch(this::isPrime);
System.out.println("List contains a prime number: " + containsPrime);
}
}
