Regular expressions, commonly abbreviated as "regex" or "regexp", are powerful patterns used for string matching and manipulation. Originating from formal language theory in computer science, they have become an indispensable tool in text processing, data validation, and search operations across programming and scripting languages. By defining specific patterns of characters, regex allows users to identify, extract, replace, or split strings in ways that simple string methods cannot achieve, making them a cornerstone of sophisticated text manipulation in software development.
The regex I will be explaining is used for verifying that a piece of user input is a valid email address: /^(\w+|[0-9]+)@\w+\.\w/i