Merge pull request mouredev#7263 from danhingar/ejercicio22

#22 - Java

Author: kontroldev

Roadmap/22 - FUNCIONES DE ORDEN SUPERIOR/java/danhingar.java

@@ -0,0 +1,101 @@
+import java.time.LocalDate;
+import java.util.Comparator;
+import java.util.Date;
+import java.util.List;
+import java.util.function.Function;
+
+public class danhingar {
+
+    public static void main(String[] args) {
+        System.err.println(applyFunc(String::length, "Daniel"));
+
+        Function<Integer, Integer> number = applyMultiplier(5);
+        int result = number.apply(5);
+        System.out.println(result);
+
+        List<Integer> numbers = List.of(1, 3, 4, 2, 5);
+        System.out.println(numbers.stream().map(num -> num * 2).toList());
+
+        System.out.println(numbers.stream().filter(num -> num % 2 == 0).toList());
+
+        System.out.println(numbers.stream().sorted().toList());
+
+        System.out.println(numbers.stream().sorted(Comparator.reverseOrder()).toList());
+
+        System.out.println(numbers.stream().reduce(0, Integer::sum));
+
+        // EXTRA
+        List<Student> students = List.of(
+                new Student("PEPE", java.sql.Date.valueOf(LocalDate.parse("1987-04-29")), List.of(5.0, 8.5, 3.0, 10.0)),
+                new Student("JUAN", java.sql.Date.valueOf(LocalDate.parse("1995-08-04")), List.of(1.0, 9.5, 2.0, 4.0)),
+                new Student("LUIS", java.sql.Date.valueOf(LocalDate.parse("2000-12-15")), List.of(4.0, 6.5, 5.0, 2.0)),
+                new Student("MATEO", java.sql.Date.valueOf(LocalDate.parse("1980-01-25")), List.of(10.0, 9.0, 9.7, 9.9)));
+
+        //Promedio
+        System.out.println(students.stream().map(s -> String.format("%s:%.2f", s.getName(), s.average())).toList());
+
+        //Mejores
+        System.out.println(students.stream().filter(s-> s.average()>=9.0).map(Student::getName).toList());
+
+        //Fecha de nacimiento ordenada
+        System.out.println(students.stream().sorted(Comparator.comparing(Student::getBirthdate, Comparator.nullsLast(Comparator.reverseOrder()))).toList());
+
+        //Califiación más alta
+        System.out.println(students.stream().map(Student::getGrades).flatMap(List::stream).mapToDouble(Double::doubleValue).max().getAsDouble());
+    }
+
+    public static <W, X> X applyFunc(Function<W, X> function, W cadena) {
+        return function.apply(cadena);
+    }
+
+    public static Function<Integer, Integer> applyMultiplier(int n) {
+        return (number) -> number * n;
+    }
+
+}
+
+class Student {
+    private String name;
+    private Date birthdate;
+    private List<Double> grades;
+
+    public Student(String name, Date birthdate, List<Double> grades) {
+        this.name = name;
+        this.birthdate = birthdate;
+        this.grades = grades;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Date getBirthdate() {
+        return birthdate;
+    }
+
+    public void setBirthdate(Date birthdate) {
+        this.birthdate = birthdate;
+    }
+
+    public List<Double> getGrades() {
+        return grades;
+    }
+
+    public void setGrades(List<Double> grades) {
+        this.grades = grades;
+    }
+
+    public Double average() {
+        return this.grades.stream().reduce(0.0, Double::sum) / this.grades.size();
+    }
+
+    @Override
+    public String toString() {
+        return "Student [name=" + name + ", birthdate=" + birthdate + ", grades=" + grades + "]";
+    }
+
+}