2.5. Validate Input Using Regular Expressions
You need to validate that user input or data read from a file has the expected structure and content. For example, you want to ensure that a user enters a valid IP address, telephone number, or e-mail address.
Use regular expressions to ensure that the input data follows the correct structure and contains only valid characters for the expected type of information.
How It Works
When a user inputs data to your application or your application reads data from a file, it's good practice to assume that the data is bad until you have verified its accuracy. One common validation requirement is to ensure that data entries such as e-mail addresses, telephone numbers, and credit card numbers ...