What is the purpose of the preg_match() function in PHP?

The preg_match() function in PHP is designed specifically to match a given string against a specified regular expression pattern. This function evaluates whether the string adheres to the defined rules articulated in the regex, returning true if there is a match and false if there is not.

Regular expressions are powerful tools used for pattern matching within strings, allowing developers to search, validate, or manipulate strings based on complex criteria. The preg_match() function returns additional information about the match if desired, making it versatile for various string processing tasks, such as validating user input or parsing text.

In this context, the other options do not relate to the functionality of preg_match(). The function is not intended for performing calculations, escaping special characters, or formatting dates, as these tasks are accomplished by different PHP functions tailored to those specific purposes.