java集合差集

A. 用java编写程序，集合元素为小写字母，实现集合的交，并，补，差运算

public static void main(String[] args) {
Set<Character> result = new HashSet<Character>();
Set<Character> set1 = new HashSet<Character>() {
{
add('a');
add('b');
add('c');
add('d');
add('e');
}
};

Set<Character> set2 = new HashSet<Character>() {
{
add('a');
add('b');
add('c');
}
};

result.clear();
result.addAll(set1);
result.retainAll(set2);
System.out.println("交集：" + result);

result.clear();
result.addAll(set1);
result.removeAll(set2);
System.out.println("差集：" + result);

result.clear();
result.addAll(set1);
result.addAll(set2);
System.out.println("并集：" + result);

result.clear();
result.addAll(set1);
if(result.containsAll(set2)){
result.removeAll(set2);
System.out.println("补集："+result);
}else{
System.out.println("无补集");
}

}

B. java集合求差值和并集！

差集
ArrayList<String> stuList = new ArrayList<String>();
stuList.add("aa");
stuList.add("bb");
stuList.add("cc");
stuList.add("dd");
ArrayList<String> stuList2 = new ArrayList<String>();
stuList2.add("bb");
stuList2.add("cc");
stuList2.add("ee");
stuList2.add("ff");
for (String s : stuList2) {
if (stuList.contains(s)) {
stuList.remove(s);
} else {
stuList.add(s);
}
}
System.out.println(stuList2);
合集
ArrayList stuList = new ArrayList();
stuList.add("aa");
stuList.add("bb");
stuList.add("cc");
stuList.add("dd");
ArrayList stuList2 = new ArrayList();
stuList2.add("bb");
stuList2.add("cc");
stuList2.add("ee");
stuList2.add("ff");
Set set=new HashSet();
for (Object object : stuList) {
set.add(object);
}
for (Object object : stuList2) {
set.add(object);
}
System.out.println(set);

C. 用java编写程序，求集合的并集、交集和差集

publicstaticvoidmain(String[]args){
	Integer[]A={1,2,3,4};
	Integer[]B={1,3,7,9,11};
	
	List<Integer>listA=Arrays.asList(A);
	List<Integer>listB=Arrays.asList(B);
	
	List<Integer>jiaoji=newArrayList<Integer>();
	for(Integera:listA){
		if(listB.contains(a)){
			jiaoji.add(a);
		}
	}
	System.out.println(jiaoji);
	List<Integer>bingji=newArrayList<Integer>();
	for(Integera:listA){
		if(!bingji.contains(a)){
			bingji.add(a);
		}
	}
	for(Integerb:listB){
		if(!bingji.contains(b)){
			bingji.add(b);
		}
	}
	
	System.out.println(bingji);
	
	List<Integer>chaji=newArrayList<Integer>();
	for(Integera:listA){
		if(!listB.contains(a)){
			chaji.add(a);
		}
	}
	System.out.println(chaji);
}

D. java找到两个list的交集并集差集

//交集
set1.retainAll(set2);
//差集
set1.removeAll(set2);
//并集1

set1.addAll(set2);

E. Java中list集合的交集和差集的用法和如何将

只要一小句便可求出交集--> list1.retainAll(list2); list1和list2的位置无所谓，这样循环一下list1试试，如果还有多个list，一样的道理

F. Java中的Set类差集问题差集为什么是1，2不是1,2,8,9,;

如下英文是Guava中注释原文。意思是说该方法返回只存在于set1独有的数据，至于set2中独有数据和set1和set2交集的数据直接忽略。而且返回的只是不可变的Set视图，不会修改原set中数据。
/**
* Returns an unmodifiable view of the difference of two sets. The
* returned set contains all elements that are contained by set1 and
* not contained by set2. set2 may also contain elements not
* present in set1; these are simply ignored. The iteration order of
* the returned set matches that of set1.
*
* Results are undefined if set1 and set2 are sets based
* on different equivalence relations (as HashSet, TreeSet,
* and the keySet of an IdentityHashMap all are).
*/