Java regex check if certain characters match pattern

Question

I need your help with regex. This is my requirement, check string if it starts with 0937, 937 or 63937. Next check if string ONLY contains digits and check if length of characters for 0937 = 11, 937 = 10, 63937 = 12.

So far this is what I've tried:

class MyRegex {

static Pattern p1 = Pattern.compile("^0937[0-9]{11}+$");
static Pattern p2 = Pattern.compile("^937[0-9]+{10}$");
static Pattern p3 = Pattern.compile("^63937[0-9]{12}$");

 public static void main(String []args){

    String phone = "09375126435"; //"639375126439"; // "9375126435";

    System.out.println(validateABSMobileNumber(phone));
 }

 public static boolean validateABSMobileNumber(String phone){
    return p1.matcher(phone).matches() || p2.matcher(phone).matches() || p3.matcher(phone).matches() ;
}

}

Sample test cases:

09375126435 = true 0937512643 = false 639375126439 = true 63937512643 = false 9375126439 = true 937512643 = false

But it doesn't run correctly. Any ideas how to fix this? Thanks.

Your requirements mean that a regex is not that necessary here. String.startsWith() + StringUtils.isNumeric + String.length() can be used. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Feb 16, 2016 at 9:26
StringUtils requires an external library, and I see nothing wrong with using regex here. — Tim Biegeleisen
– Tim Biegeleisen, Commented Feb 16, 2016 at 9:31
NumberFormat.getInstance().parse(value) can be used instead of StringUtils.isNumeric. No one says a regex is a wrong way. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Feb 16, 2016 at 9:32

Tim Biegeleisen · Accepted Answer · 2016-02-16 09:27:33Z

2

Your patterns were counting characters incorrectly. Use this:

static Pattern p1 = Pattern.compile("^0937[0-9]{7}$");
static Pattern p2 = Pattern.compile("^937[0-9]{7}$");
static Pattern p3 = Pattern.compile("^63937[0-9]{7}$");

answered Feb 16, 2016 at 9:27

Tim Biegeleisen

526k32 gold badges323 silver badges399 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Wiktor Stribiżew Over a year ago

Why use 3 different patterns when you can use 1? And why do you think OP solution "counted" characters incorrectly? :)

Tim Biegeleisen Over a year ago

This code is readable, and sometimes this is more valuable than having a slick looking (and non maintainable) regex.

Tim Biegeleisen Over a year ago

@WiktorStribiżew His original patterns were matching the initial portion plus the entire length of what he wanted. To put it another way, in the first pattern he wants 11 characters total, but he was matching 11 characters after the initial pattern, for a total of 15 characters.

Wiktor Stribiżew Over a year ago

So, it is not patterns that are to blame, it is a logical error made by OP. And the problem is different in the second regex.

hmrojas.p · Accepted Answer · 2016-02-17 20:40:38Z

1

I think you can use only one pattern, something like this:

static Pattern p = Pattern.compile("^((0937)|(937)|(63937))[0-9]{7}$");

This patter include your three cases with the correct length. So if you can have a maintable regex, I recommend you to use a properties file.

I hope this information helps you.

Good luck.

answered Feb 17, 2016 at 20:40

hmrojas.p

5821 gold badge5 silver badges15 bronze badges

Collectives™ on Stack Overflow

Java regex check if certain characters match pattern

2 Answers 2

4 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related