1. What are Regular Expressions
The main purpose of regular expressions, also called regex or regexp, is to efficiently search for patterns in a given text. These search patterns are written using a special format which a regular expression parser understands.
Regular expressions are originating from Unix systems, where a program was designed, called grep, to help users work with strings and manipulate text. By following a few basic rules, one can create very complex search patterns.
As an example, let’s say you’re given the task to check wether an e-mail or a telephone number has the correct form. Using a few simple commands these problems can easily be solved thanks to regular expressions. The syntax doesn’t always seems straightforward at first, but once you learn it, you’ll realize that you can do pretty complex searches easily, just by typing in a few characters and you’ll approach problems from a different perspective.
