April 5th, 2023
Collection sort
Sort collection using stream and Lambda functions.
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;
public class Sorter1 {
public static void main(String[] args) {
List<Student> students = new ArrayList<>();
students.add(new Student("A", 10));
students.add(new Student("B", 12));
students.add(new Student("C", 8));
students.add(new Student("D", 9));
students.add(new Student("E", 11));
students.add(new Student("F", 14));
System.out.println("=== Before Sort ============");
students.forEach(i -> System.out.println(i.toString()));
List<Student> list1 = students.stream().sorted(Comparator.comparing(Student::getAge)).collect(Collectors.toList());
// OR
List<Student> list1 = students.stream().sorted((a,b) -> a.getAge().compareTo(b.getAge())).collect(Collectors.toList());
System.out.println("\n=== After Sort ============");
list1.forEach(i -> System.out.println(i.toString()));
}
}
Sort collection without stream.
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
public class Sorter1 {
public static void main(String[] args) {
List<Student> students = new ArrayList<>();
students.add(new Student("A", 10));
students.add(new Student("B", 12));
students.add(new Student("C", 8));
students.add(new Student("D", 9));
students.add(new Student("E", 11));
students.add(new Student("F", 14));
System.out.println("=== Before Sort ============");
students.forEach(i -> System.out.println(i.toString()));
students.sort(Comparator.comparing(Student::getAge));
// OR
students.sort((a,b)->a.getAge().compareTo(b.getAge()));
System.out.println("\n=== After Sort ============");
students.forEach(i -> System.out.println(i.toString()));
}
}
class Student{
private String name;
private Integer age;
public Student(String name, int age) {
this.name = name;
this.age = age;
}
public String toString() {
return this.name+" : "+ this.age;
}
public String getName() {
return name;
}
public Integer getAge() {
return age;
}
}
=== Before Sort ============
A : 10
B : 12
C : 8
D : 9
E : 11
F : 14
=== After Sort ============
C : 8
D : 9
A : 10
E : 11
B : 12
F : 14
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