Regex Tutorial

Regex is a powerful way to work with strings. It has many components such as anchors, qualifiers, or operators, character classes, flags and more.

Summary

The following regex is an example of a string separator using regex. With this regex patter you can separate any type of phone number layout into first, second and third sections.

.?(\\d{3}).*(\\d{3}).*(\\d{4})

OR Operator
Character Classes
Grouping and Capturing
Bracket Expressions

Regex Components

OR Operator

.? - 0 or 1 character to account for the optional open parenthesis

.* - 0 or more characters to account for the optional closing parenthesis, hyphen, and space characters

.* 0 or more characters to account for the optional hyphen and space characters

Character Classes

(\\d{3}) - 3 digit characters (first capture group i.e. first 3 digits)

(\\d{3}) 3 digit characters (second capture group i.e. next 3 digits)

(\\d{4}) 4 digit characters (third capture group i.e. last 4 digits)

Grouping and Capturing