1.set集合类型取交集/并集/差集
1 String[] str1={"a","b","c","d","e"}; 2 String[] str2={"d","e","f","g","h"}; 3 4 Set<String> set1 = new HashSet<String>(Arrays.asList(str1)); 5 Set<String> set2 = new HashSet<String>(Arrays.asList(str2)); 6 Set<String> set = new HashSet<String>(); 7 System.out.println("集" + set2); 8 // 并集 9 set.addAll(set1); 10 set.addAll(set2); 11 System.out.println("并集" + set); 12 13 // 交集 14 set.clear(); 15 set.addAll(set1); 16 set.retainAll(set2); 17 System.out.println("交集" + set); 18 // 差集 19 set.clear(); 20 set.addAll(set1); 21 set.removeAll(set2); 22 System.out.println("差集" + set);
2.给字符串中每两位字符加一个空格
1 String input = "abcdefghijk"; 2 String regex = "(.{2})"; 3 input = input.replaceAll (regex, "$1 "); 4 System.out.println (input);
