Learn Regex - This section will help you to find best Regular Expressions Tutorials & Courses recommended by experts. A regular expression, regex or regexp (sometimes called a rational expression) is a sequence of characters that define a search pattern.Learn to use regular expressions to search for text patterns, validate emails and URLs. Here You will find some of the best Regex Tutorials, each course has its details like (Video or text, free or paid, beginners or expert level) which helps you to choose the best Regex course easily.