Example usage for java.util List stream

Introduction

In this page you can find the example usage for java.util List stream.

Prototype

default Stream<E> stream()

Source Link

Document

Returns a sequential Stream with this collection as its source.

Usage

From source file:Main.java

public static void main(String[] args) {

    List<String> friends = Arrays.asList("CSS", "HTML", "Oracle", "Dart");

    Comparator<String> compByLength = (aName, bName) -> aName.length() - bName.length();
    friends.stream().sorted(compByLength).forEach(System.out::println);
}

From source file:Main.java

public static void main(String[] args) {
    List<Trade> trades = TradeUtil.createTrades();

    Map<String, List<Trade>> issuers = trades.stream().collect(Collectors.groupingBy(t -> t.getIssuer()));

    System.out.println("Grouped List: " + issuers);
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    List<Person> persons = Arrays.asList(new Person("Max", 18), new Person("Peter", 23),
            new Person("Pamela", 23), new Person("David", 12));

    persons.stream().reduce((p1, p2) -> p1.age > p2.age ? p1 : p2).ifPresent(System.out::println); // Pamela
}

From source file:Main.java

public static void main(String[] args) {
    List<Person> roster = createRoster();
    double average = roster.stream().filter(p -> p.getGender() == Person.Sex.MALE).mapToInt(Person::getAge)
            .average().getAsDouble();//from w ww.j  a v a  2  s  . c om

    System.out.println("Average age of male members (bulk data operations): " + average);
}

From source file:Main.java

public static void main(String[] argv) {
    List<Person> persons = Arrays.asList(new Person("Joe", 12), new Person("Jim", 34), new Person("John", 23));

    Stream<Person> personsOver18 = persons.stream().filter(p -> p.getAge() > 18);
    personsOver18.forEach(p -> System.out.println(p.getFirstName()));

}

From source file:Ran.java

public static void main(String[] args) {

    // Get and shuffle the list of arguments
    List<String> argList = Arrays.asList(args);
    Collections.shuffle(argList);

    // Print out the elements using JDK 8 Streams
    argList.stream().forEach(e -> System.out.format("%s ", e));

    // Print out the elements using for-each
    for (String arg : argList) {
        System.out.format("%s ", arg);
    }//from  w ww.  j av a  2  s. c om

    System.out.println();
}

From source file:Main.java

public static void main(String[] args) {
    List<Employee> persons = Employee.persons();
    System.out.println("Before increasing the   income:   " + persons);

    persons.stream().filter(Employee::isFemale).forEach(p -> p.setIncome(p.getIncome() * 1.10));

    System.out.println("After increasing the   income:   " + persons);
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    List<Person> persons = Arrays.asList(new Person("Max", 18), new Person("Peter", 23),
            new Person("Pamela", 23), new Person("David", 12));

    Integer ageSum = persons.stream().reduce(0, (sum, p) -> sum += p.age, (sum1, sum2) -> sum1 + sum2);

    System.out.println(ageSum);//from   w w w .ja  va  2  s. c o  m
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    List<Person> persons = Arrays.asList(new Person("Max", 18), new Person("Peter", 23),
            new Person("Pamela", 23), new Person("David", 12));

    String names = persons.stream().filter(p -> p.age >= 18).map(p -> p.name)
            .collect(Collectors.joining(" and ", "In Germany ", " are of legal age."));

    System.out.println(names);/* w  w w .j a v  a 2s.  c o  m*/
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    List<Person> persons = Arrays.asList(new Person("Max", 18), new Person("Peter", 23),
            new Person("Pamela", 23), new Person("David", 12));

    Double averageAge = persons.stream().collect(Collectors.averagingInt(p -> p.age));

    System.out.println(averageAge); // 19.0
}