Regular expression to find repeat number not working

Question

We want to check if number has repeat sequence for example - 111111 , 222222 etc. Below is the code :

String input = "222222";

public static String REGEX_REPEAT = "([\\d])\1{2}";

Pattern pattern = Pattern.compile(REGEX_REPEAT);
Matcher matcher = pattern.matcher(input.trim());
return matcher.matches();

But it always return false. I tried below regular expression also "([\\d])\\1{2}"

Any Help appreciated.

Thanks

[This answer might help](https://stackoverflow.com/a/6508030/9678116) — Jahanvi Kariya, Dec 23 '19 at 06:53
Same regular expression is working fine when I test it on online tool https://regex101.com/ . But It is not working from android code. I try with various combinations thought escape character issue but nothing works. — Praveen Mishra, Dec 23 '19 at 07:09
@Androiddeveloper you can use this "^(\\d)\\1+$" Also added the answer. — Nikunj, Dec 23 '19 at 07:34
The `matches` method checks the whole string. Use the `find` method instead. — Casimir et Hippolyte, Dec 23 '19 at 07:40
(\\d)\\1{3,} This expression work for me. Hope it will help someone has same issue. — Praveen Mishra, Dec 23 '19 at 08:34

score 1 · Answer 1 · answered Dec 23 '19 at 07:32

1

Replace this

String REGEX_REPEAT = "([\\d])\1{2}";

with

String REGEX_REPEAT = "^(\\d)\\1+$";

answered Dec 23 '19 at 07:32

Nikunj

3,937
19
33

score 0 · Answer 2 · answered Dec 23 '19 at 07:01

You can use following code

    import java.util.regex.*; 
class FindRepeatSequence {

    static boolean returnMatch(String input){
   String REGEX_REPEAT = "(\\w)\\1+";
   Pattern pattern = Pattern.compile(REGEX_REPEAT);
        Matcher matcher = pattern.matcher(input.trim());
    return matcher.matches();
    }

    public static void main(String[]args){
      String input = "222222";

     System.out.println("Print"+returnMatch(input));
    }
}

score 0 · Answer 3 · answered Dec 23 '19 at 07:02

0

if you want to check the duplicate just use

   (\d)\1+\b

and if you want to check duplicate with limit use

  //  (\d)\1{number_limit}\b   eg: 

     (\d)\1{3}\b

answered Dec 23 '19 at 07:02

Sahjad Ansari

69
5

Not working in android code – Praveen Mishra Dec 23 '19 at 07:27
are you using user_String.matches(regex) ? eg: "11232332".matches("(\d)\1+\b ") – Sahjad Ansari Dec 23 '19 at 08:27
thie expression (\\d)\\1{3,} is working for me. – Praveen Mishra Dec 23 '19 at 08:36

Regular expression to find repeat number not working

3 Answers3