设置差异（）函数|番石榴 |Java

Guava 的Sets.difference()返回两个集合差异的不可修改视图。

句法：

public static  
  Sets.SetView 
    difference(Set set1,
               Set set2)

返回值：此方法返回一个集合，该集合包含 set1 包含但 set2 不包含的所有元素。

注意： Set2 也可能包含 set1 中不存在的元素，这些被简单地忽略。返回集合的迭代顺序与 set1 的迭代顺序一致。

示例 1：

// Java code to show implementation of
// Guava's Sets.difference() method
  
import com.google.common.collect.Sets;
import java.util.Set;
  
class GFG {
    // Driver's code
    public static void main(String[] args)
    {
        // Creating first set named set1
        Set
            set1 = Sets.newHashSet(1, 2, 3, 4, 5, 6);
  
        // Creating second set named set2
        Set
            set2 = Sets.newHashSet(1, 3, 5, 7);
  
        // Using Guava's Sets.difference() method
        Set
            diff = Sets.difference(set1, set2);
  
        // Displaying the unmodifiable view of
        // the difference of two sets.
        System.out.println("Set 1: "
                           + set1);
        System.out.println("Set 2: "
                           + set2);
        System.out.println("Difference between "
                           + "Set 1 and Set 2: "
                           + diff);
    }
}

输出：

Set 1: [1, 2, 3, 4, 5, 6]
Set 2: [1, 3, 5, 7]
Difference between Set 1 and Set 2: [2, 4, 6]

示例 2：

// Java code to show implementation of
// Guava's Sets.difference() method
  
import com.google.common.collect.Sets;
import java.util.Set;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
  
        // Creating first set named set1
        Set
            set1 = Sets
                       .newHashSet("H", "E", "L", "L", "O", "G");
  
        // Creating second set named set2
        Set
            set2 = Sets
                       .newHashSet("L", "I", "K", "E", "G");
  
        // Using Guava's Sets.difference() method
        Set
            diff = Sets.difference(set1, set2);
  
        // Displaying the unmodifiable view of
        // the difference of two sets.
        System.out.println("Set 1: "
                           + set1);
        System.out.println("Set 2: "
                           + set2);
        System.out.println("Difference between "
                           + "Set 1 and Set 2: "
                           + diff);
    }
}

输出：

Set 1: [E, G, H, L, O]
Set 2: [I, K, L, E, G]
Difference between Set 1 and Set 2: [H, O]