Regular Expressions allow developers to match, parse and replace text based on virtually limitless criteria. With Regular Expressions, you can Validate an Email Address or a Url, easily find information in a massive text file, extract pieces of information from a 3rd party’s proprietary file format and much, much more. Most Regular Expressions usually take a single line of code and can replace dozens or hundreds of lines of complex nested looping and string parsing logic. Knowledge of these powerful statements is a must for every proficient developer.