Java HashSet 集合

import java.util.HashSet; // 导入 HashSet 类

HashSet cars = new HashSet();

// 导入 HashSet 类
import java.util.HashSet;

public class MyClass {
  public static void main(String[] args) {
    HashSet cars = new HashSet();
    cars.add("Volvo");
    cars.add("BMW");
    cars.add("Ford");
    cars.add("BMW");
    cars.add("Mazda");
    System.out.println(cars);
  }
}

cars.contains("Mazda");

cars.remove("Volvo");

cars.clear();

cars.size();

for (String i : cars) {
  System.out.println(i);
}

import java.util.HashSet;

public class MyClass {
  public static void main(String[] args) {

    // 创建一个名为 numbers 的 HashSet 对象
    HashSet numbers = new HashSet();

    // 将值添加到集合
    numbers.add(4);
    numbers.add(7);
    numbers.add(8);

    // 显示 1 到 10 之间的数字在集合中
    for(int i = 1; i <= 10; i++) {
      if(numbers.contains(i)) {
        System.out.println(i + " was found in the set.");
      } else {
        System.out.println(i + " was not found in the set.");
      }
    }
  }
}