how to extract a phone number for a string using regular expression?

Question

If I have a string that contains the following: This is 1 test 123-456-7890
I need to extract 1234567890 as a phone number. I don't want to extract the number 1 that is before test.
How can I do that using regular expressions in java?

I know a way but I am not sure if it is the best solution:

String inputString = "This is 1 test 123-456-7890";
string result =  inputString.replaceAll("(\\d{3})-(\\d{3})-(\\d{4})",""); 
String phoneNumber = inputString.replace(result, "");

Answer 1

The best and standard way is use libphonenumber. There is a findNumbers function you can use. Here is a code snippet

public static void  extractPhoneNumber(String input){


    Iterator<PhoneNumberMatch> existsPhone=PhoneNumberUtil.getInstance().findNumbers(input, "IN").iterator();

    while (existsPhone.hasNext()){
        System.out.println("Phone == " + existsPhone.next().number());
    }
}

Answer 2

The following code will check for the phone number in the string you mention and print it:

String str = "This is 1 test 123-456-7890";

Pattern pattern = Pattern.compile("\\d{3}-\\d{3}-\\d{4}");
Matcher matcher = pattern.matcher(str);
if (matcher.find()) {
    System.out.println(matcher.group(0));
}

But, as pointed out in other answers, many phone numbers (especially not international ones) will not match the pattern.