英文:
I have a PriorityQueue of Objects and I need to sort it based on float values.How do I create a comparator for it?
问题
我已经为优先队列创建了一个比较器。
class CompareBySalary implements Comparator<Employee> {
    @Override
    public int compare(Employee e1, Employee e2) {
        return e1.salary < e2.salary ? -1 : e1.salary > e2.salary ? 1 : 0;
    }
}
class Employee {
    String name;
    float salary;
    Employee(String name, float salary) {
        this.name = name;
        this.salary = salary;
    }
}
public class TryCode {
    public static void main(String args[]) {
        Employee e1 = new Employee("C", 10000);
        Employee e2 = new Employee("A", 5000.45f);
        Employee e3 = new Employee("D", 15000);
        Employee e4 = new Employee("B", 5000.67f);
        Queue<Employee> q = new PriorityQueue(new CompareBySalary());
        q.offer(e1);
        q.offer(e2);
        q.offer(e3);
        q.offer(e4);
        for (Employee e : q)
            System.out.println(e.name);
    }
}
这会输出:A B D C
为什么它没有正确排序?
有什么我漏掉的东西吗?
附注:我已经尝试使用Float.compare(),它也会给出相同的输出。
英文:
I have already created a comparator for the priority queue.
class CompareBySalary implements Comparator<Employee>{
    @Override
    public int compare(Employee e1,Employee e2){
        return e1.salary<e2.salary ? -1 : e1.salary>e2.salary ? 1 : 0;
        
    }
}
class Employee{
    String name;
    float salary;
    Employee(String name,float salary){
        this.name=name;
        this.salary=salary;
    }
}
 public class TryCode{
     
     public static void main(String args[])
     {
        
         Employee e1=new Employee("C",10000);
         Employee e2=new Employee("A",5000.45f);
         Employee e3=new Employee("D",15000);
         Employee e4=new Employee("B",5000.67f);
         Queue<Employee> q=new PriorityQueue(new CompareBySalary());
         q.offer(e1);
         q.offer(e2);
         q.offer(e3);
         q.offer(e4);
         for(Employee e:q)
             System.out.println(e.name);
            
     }
     
     
 }
This gives the output:A B D C
Why is it not sorting correctly?
Is it something I am missing?
P.S. I have already tried with Float.compare() it gives the same output.
答案1
得分: 0
- 更改你的领域模型如下:
 
class Employee implements Comparable<Employee> {
    private String name;
    private float salary;
    Employee(String name, float salary) {
        this.name = name;
        this.salary = salary;
    }
    public String getName() {
        return name;
    }
    public float getSalary() {
        return salary;
    }
    @Override
    public int compareTo(Employee o) {
        if (this.getSalary() > o.getSalary()) {
            return 1;
        } else if (this.getSalary() < o.getSalary()) {
            return -1;
        } else {
            return 0;
        }
    }
}
- 
移除
CompareBySalary(你将不再需要它) - 
创建你的
PriorityQueue如下: 
PriorityQueue<Employee> q = new PriorityQueue<>(Comparator.comparingDouble(Employee::getSalary));
英文:
- 
Change your domain model as follows:
class Employee implements Comparable<Employee> { private String name; private float salary; Employee(String name, float salary) { this.name = name; this.salary = salary; } public String getName() { return name; } public float getSalary() { return salary; } @Override public int compareTo(Employee o) { if (o1.getSalary()>o2.getSalary()) { return 1; } else if (o1.getSalary()<o2.getSalary()) { return -1; } else { return 0; } } } - 
Remove
CompareBySalary(you won't need it) - 
Create your
PriorityQueuelike this:PriorityQueue<Employee> q = new PriorityQueue<>(Comparator.comparingDouble(Employee::getSalary)); 
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库,让每个人都能够通过互相帮助和分享经验来进步。


评论