正则表达式学习笔记

 1 public class Test {
 2 
 3     public static void main(String[] args) {
 4 
 5         String str = "abcdabababbbbb";
 6         String regEx1 = "(a(b))cd\\1+\\2{4}"; //表示第一组"(ab)出现一次以上，第二组"(b)"出现四次
 7         boolean b = str.matches(regEx1);
 8         System.out.println(b);//true
 9 
10         String str2 = "aaabbbbbbbccaaaaddddddddddddd";
11         String regEx2 = "(.)\\1+"; //表示任意字符（除"\n"外）练习出现一次以上
12         String ss = str.replaceAll(regEx2, "$1"); //将连续重复的字符替换第一个字符
13         System.out.println(ss); //"abcdababab"
14 
15         //将字符串str3转换成 "我爱编程"
16         String str3 = "我..我....我...我......爱..爱...爱.....爱...编.....编....编..编....程....程...程....程!";
17         //方法一
18         //(?=X) X，通过零宽度的正lookahead,表示不理解
19         String regEx3 = "(.)(?=.*\\1)";
20         String a = str3.replaceAll (regEx3,"");
21         System.out.println (a); //我爱编.程!
22         // "\\p{Punct}"表示匹配 标点符号：!"#$%&‘()*+,-./:;<=>?@[\]^_`{|}~
23         System.out.println (a.replaceAll ("\\p{Punct}",""));//我爱编程
24 
25         //方法二
26         str3 = str3.replaceAll("(我\\.+)+(爱\\.+)+(编\\.+)+(程\\.+)+(程\\!+)","我爱编程");
27         System.out.println (str3); //我爱编程
28 
29         //方法三
30         str3 = str3.replaceAll ("[.!]","")
31                 .replaceAll ("(.)\\1+","$1");
32         System.out.println (str3); //我爱编程
33     }
34 }