CODEWITHSUNDEEP
javaregex
sweetie
sweetie

Reputation: 63

Regex to allow only 10 or 16 digit comma separated number

I want to validate a textfield in a Java based app where I want to allow only comma separated numbers and they should be either 10 or 16 digits. I have a regex that ^[0-9,;]+$ to allow only numbers, but it doesn't work for 10 or 16 digits only.

Upvotes: 3

Views: 4135

Answers (4)

Jan
Jan

Reputation: 13858

You can use {n,m} to specify length.

So matching one number with either 10 or 16 digits would be

^(\d{10}|\d{16})$

Meaning: match for exactly 10 or 16 digits and the stuff before is start-of-line and the stuff behind is end-of-line.

Now add separator:

^((\d{10}|\d{16})[,;])*(\d{10}|\d{16})$

Some sequences of 10-or-16 digit followed by either , or ; and then one sequece 10-or-16 with end-of-line.

You need to escape those \ in java.

public static void main(String[] args) {
    String regex = "^((\\d{10}|\\d{16})[,;])*(\\d{10}|\\d{16})$";
    String y = "0123456789,0123456789123456,0123456789";
    System.out.println(y.matches(regex)); //Should be true
    String n = "0123456789,01234567891234567,0123456789";
    System.out.println(n.matches(regex)); //should be false
  }

Upvotes: 1

pguardiario
pguardiario

Reputation: 54984

You need to have both anchors and word boundaries:

/^(?:\b(?:\d{10}|\d{16})\b,?)*$/

The anchors are necessary so you don't get false positives for partial matches and the word boundaries are necessary so you don't get false positives for 20, 26, 30, 32 digit numbers.

Upvotes: 0

AlexR
AlexR

Reputation: 115328

Here is my version

(?:\d+,){9}\d+|(?:\d+,){15}\d+

Let's review it. First of all there is a problem to say: 10 or 16. So, I have to create actually 2 expressions with | between them.

Second, the expression itself. Your version just says that you allow digits and commas. However this is not what you really want because for example string like ,,, will match your regex.

So, the regex should be like (?:\d+,){n}\d+ that means: sequence of several digits terminated by comma and then sequence of several digits, e.g. 123,45,678 (where 123,45 match the first part and 678 match the second part)

Finally we get regex that I have written in the beginning of my answer: 

(?:\d+,){9}\d+|(?:\d+,){15}\d+

And do not forget that when you write regex in you java code you have to duplicate the back slash, like this:

Pattern.compile("\\d+,{9}\\d+|\\d+,{15}\\d+")

EDIT: I have just added non-capturing group (?: ...... )

Upvotes: -1

ug_
ug_

Reputation: 11440

I would probably use this regex:

(\d{10}(?:\d{6})?,?)+

Explanation:

(          - Begin capture group
  \d{10}   - Matching at least 10 digits
  (?:      - Begin non capture group 
     \d{6} - Match 6 more digits
  )?       - End group, mark as optional using ?
  ,?       - optionally capture a comma
)+         - End outer capture group, require at least 1 or more to exist? (mabye change to * for 0 or more)

The following inputs match this regex

1234567890123456,1234567890 
1234567890123456
1234567890

these inputs do not match

123,1234567890
12355
123456789012

Upvotes: 1

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