Java之两个Set集合的交集、差集和并集

蔚落 2023-06-08 03:29 60阅读 0赞

Java之两个Set集合的交集、差集和并集  
一、求交集

注：场景是读取两个文件，把文件内容放到Set中，求两个文件之间的共同元素。在这里只写对Set的操作。

public static void main(String[] args) throws Exception {
    		String path1 = "path1";
    		String path2 = "path2";
    		Set<String> set1 = readFile(path1);
    		Set<String> set2 = readFile(path2);
    		Set<String> set = new HashSet<String>();
    		set.addAll(set1);
    		set.retainAll(set2);
    		System.out.println(set);
    }

二、求差集

1）、获取在set1而不在set2中的元素

public static void main(String[] args) throws Exception {
    		String path1 = "path1";
    		String path2 = "path2";
    		Set<String> set1 = readFile(path1);
    		Set<String> set2 = readFile(path2);
    		Set<String> set = new HashSet<String>();
    		set.addAll(set1);
    		set.removeAll(set2);
    		System.out.println(set);
    }

2）、获取在set2不在set1中的元素

public static void main(String[] args) throws Exception {
    		String path1 = "path1";
    		String path2 = "path2";
    		Set<String> set1 = readFile(path1);
    		Set<String> set2 = readFile(path2);
    		Set<String> set = new HashSet<String>();
    		set.addAll(set2);
    		set.removeAll(set1);
    		System.out.println(set);
    }

三、求并集

public static void main(String[] args) throws Exception {
    		String path1 = "path1";
    		String path2 = "path2";
    		Set<String> set1 = readFile(path1);
    		Set<String> set2 = readFile(path2);
    		Set<String> set = new HashSet<String>();
    		set.addAll(set2);
    		set.addAll(set1);
    		System.out.println(set);
    }