Regex

=Syntax=

=Examples= 1. To Match upto 999.999.999.999: \b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b OR shortened with a quantifier to: \b(?:\d{1,3}\.){3}\d{1,3}\b 2. To match exactly upto 255.255.255.255:  \b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b OR shortened with a quantifier to: \b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b
 * For IP Addresses:

1. Visa card numbers start with a 4. New cards have 16 digits. Old cards have 13: ^4[0-9]{12}(?:[0-9]{3})?$ 2. MasterCard numbers start with the numbers 51 through 55. All have 16 digits: ^5[1-5][0-9]{14}$
 * For Credit Card numbers: