A Tip A Day #7 – US Phone Validation Using RegEx

This post is a part of the daily blog series 

A Tip A Day, daily dosage of learning!

 Day #7 – US Phone Validation Using RegEx (Regular Expression)

US Phone Number :  222-333-4444

String phone = '222-333-4444';
String WrongPhone = '222-333'

//This is the pattern that matches with the above phone number format
String regExPhone = '^[0-9]\\d{2}-\\d{3}-\\d{4}$';

//The below result would give TRUE, because the pattern matches with String Phone 
Boolean valid = Pattern.matches(regExPhone,phone);

//Checking the pattern match for WrongPhone.  This would result in FALSE
Boolean valid2 = Pattern.matches(regExPhone,WrongPhone);

US Phone Number With Extension: 222-333-4444×1234

String phone = '222-333-4444';
String phoneWithExtn = '222-333-4444x1234'

//This is the pattern that matches with the above phone number format
String regExPhoneWithExtn = '^[0-9]\\d{2}-\\d{3}-\\d{4}x\\d*$';

//The below result would give TRUE, because the pattern matches with String PhoneWithExtn 
Boolean valid = Pattern.matches(regExPhoneWithExtn,phoneWithExtn);

//Checking the pattern match for just phone. This would result in FALSE
Boolean valid = Pattern.matches(regExPhoneWithExtn,phone);

Useful Links

The 2 links below help to test your regular expressions and also explain how to build regular expressions for different string formats.  You can learn to build the regular expressions.  Give a try.

http://regexr.com/

http://regexlib.com/RETester.aspx?regexp_id=22

Read all other tips of the blog series here – A Tip A Day, daily dosage of learning!